CN113773513B - Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof - Google Patents

Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof Download PDF

Info

Publication number
CN113773513B
CN113773513B CN202111001160.4A CN202111001160A CN113773513B CN 113773513 B CN113773513 B CN 113773513B CN 202111001160 A CN202111001160 A CN 202111001160A CN 113773513 B CN113773513 B CN 113773513B
Authority
CN
China
Prior art keywords
hyaluronic acid
graphite alkyne
flame
flame retardant
retardant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202111001160.4A
Other languages
Chinese (zh)
Other versions
CN113773513A (en
Inventor
胡英
颜志勇
王晓馨
钟楚涛
于利超
易洪雷
李喆
姚勇波
生俊露
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiaxing University
Original Assignee
Jiaxing University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiaxing University filed Critical Jiaxing University
Priority to CN202111001160.4A priority Critical patent/CN113773513B/en
Publication of CN113773513A publication Critical patent/CN113773513A/en
Application granted granted Critical
Publication of CN113773513B publication Critical patent/CN113773513B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G83/00—Macromolecular compounds not provided for in groups C08G2/00 - C08G81/00
    • C08G83/001—Macromolecular compounds containing organic and inorganic sequences, e.g. organic polymers grafted onto silica
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2201/00—Properties
    • C08L2201/02—Flame or fire retardant/resistant

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

The invention relates to a graphite alkyne-hyaluronic acid composite flame retardant and a preparation method and application thereof.A sulfhydrylation hyaluronic acid and a reducing agent I are added into a dispersion liquid of activated graphite alkyne, and click reaction is carried out under the condition of an initiator to obtain the graphite alkyne-hyaluronic acid composite flame retardant; the structural formula of the prepared graphite alkyne-hyaluronic acid composite flame retardant is shown in the specification

Description

Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof
Technical Field
The invention belongs to the technical field of flame retardants, and relates to a graphite alkyne-hyaluronic acid composite flame retardant, and a preparation method and application thereof.
Background
The green environmental protection fire retardant such as halogen-free fire retardant is highly appreciated because of its characteristics of high efficiency, low smoke, low toxicity, etc. With the continuous improvement of the environment-friendly requirement of people on the polymer flame-retardant system, the high polymer and organic or inorganic nano composite material flame retardant is bound to become the key point of the next research due to the advantages of excellent flame-retardant property, physical property, no toxicity, no pollution and the like. However, in the prior art (the research on the surface modification of inorganic particle flame retardant, Guangdong chemical 2021,48(02)), the organic or inorganic nanocomposite flame retardant has several problems: (1) the inorganic nano material is easy to agglomerate, difficult to uniformly disperse in a polymer matrix, poor in compatibility with a high polymer material, and often subjected to phase separation when doped into the high polymer matrix material, so that the mechanical property cannot meet the actual requirement; (2) the formed flame-retardant material has poor thermal stability and low carbon residue rate, and a firm and stable carbon residue layer can not be formed in the combustion process to protect the base material. For example, organic flame retardant materials such as additive phosphate flame retardant materials have good flame retardant effect, but have the defects of easy volatilization, easy migration, low carbon residue rate, serious molten drop phenomenon and the like; (3) when the addition amount is large (10-60%), the mechanical property of the material is reduced. For example, the high-molecular material filling amount of the magnesium hydroxide nanoparticles must be more than 50% to obtain a considerable flame retardant effect, and the magnesium hydroxide has poor compatibility with the polymer matrix, so that the high-molecular material filling amount cannot be uniformly dispersed in the polymer matrix, which greatly reduces the mechanical properties and the processability of the polymer material.
In order to overcome the defects that inorganic nano materials are easy to agglomerate and poor in compatibility with high polymer materials, the inorganic nano materials are modified by organic matters, for example, hydrotalcite particles are easy to agglomerate and poor in compatibility with the high polymer materials, molybdenum-containing hydrotalcite is modified by lauryl sulfuric acid and octadecanoic acid organic anions, the multi-phase synergistic effect of an organic molecular phase, a molybdenum phase and the hydrotalcite is achieved, and the problems that the hydrotalcite is easy to agglomerate and poor in dispersibility in a high polymer matrix material are solved.
Similarly, in order to solve the problem of poor interface compatibility between graphene and a polymer, in patent CN202011161817.9, an organic amine molecule is introduced to the surface of graphene oxide, and then the graphene oxide molecule reacts with divinylbenzene-maleic anhydride copolymer microspheres and phenylphosphoryl dichloride to improve the polarity of the surface of graphene, and the graphene oxide molecule and polyamide generate a chemical bonding effect to reduce the influence of graphene on the mechanical properties of polyamide to a certain extent. However, when the total amount of the graphene modified flame retardant and the phosphorus flame retardant is 12.5% -25% of the polyamide, although the flame retardant performance of the polyamide composite material is greatly improved, the compatibility of the flame retardant and the polyamide is poor due to the large addition amount of the flame retardant, and compared with a pure polyamide material, the tensile strength of the polyamide composite material is reduced by 27.4%, so that the problem of poor mechanical properties of the polyamide flame retardant composite material still needs to be further solved, when the addition amount of the flame retardant is 12.5% of the mass of the polyamide, the flame retardant grade still stays at the V-1 grade, and the flame retardant effect still needs to be improved.
In order to improve the thermal stability of the polymer, it is reported (expanded graphite and titanium dioxide synergistic flame retardant PA6 composite material and performance research thereof, 2019) that Expanded Graphite (EG) and TiO 2 After being compounded, the flame retardant is prepared from the following components in percentage by mass PA 6: EG: TiO 2 2 The melting and blending of 82:15:3 improves the decomposition temperature of the composite material, the carbon residue rate reaches 17.29 percent at most, but the EG addition amount is large, the compatibility with a matrix is poor, the interface bonding force is weak, so that more defects are generated in the material, microcracks are generated, and the tensile strength is reduced.
Therefore, the research on the novel flame retardant which has the advantages of small addition amount, good flame retardant effect, good thermal stability, high carbon residue rate, environmental protection and the like and can be applied to high polymer materials and the preparation method thereof have very important significance.
Disclosure of Invention
The invention aims to solve the problems in the prior art and provides a graphite alkyne-hyaluronic acid composite flame retardant, and a preparation method and application thereof. The invention designs and constructs a novel composite flame retardant (GDY-HA) with a cross-linked net structure by carrying out 'mercapto-alkyne' click reaction on graphite alkyne and hyaluronic acid modified by a mercapto compound. The hydrophilic hyaluronic acid and the hydrophobic graphite alkyne are combined to form a cross-linked network structure, the structure can be intertwined with a polymer matrix material chain, the compatibility with the polymer material is effectively improved, the graphite alkyne and the hyaluronic acid are mutually synergistic to form a supporting carbon layer, the carbon residue rate is improved, the heat transfer and the oxygen permeation are shielded, and the flammability of the polymer matrix material is reduced. When the doping amount of GDY-HA is not higher than 6%, the Limiting Oxygen Index (LOI) can reach 36%, the flame retardant rating is UL 94V-0, and the carbon residue rate is as high as 23.7%. The flame retardant GDY-HA HAs wide application range, and can be applied to various high polymer materials, such as nylon, polyester, polylactic acid and other high polymer materials.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a graphite alkyne-hyaluronic acid composite flame retardant has the following structural formula;
Figure BDA0003235694840000021
wherein R is
Figure BDA0003235694840000022
The carbonyl group in R is linked to the imino group, X is
Figure BDA0003235694840000023
Figure BDA0003235694840000024
Figure BDA0003235694840000031
Figure BDA0003235694840000032
Wherein Δ represents a terminal connected to the S atom, and represents a terminal connected to the carbonyl group in R, and Y represents H or-NH 2 、-COOH、-CH 3 or-SH; the value range of m + n is 53-7890, and m and n are positive integers.
The invention also provides a preparation method of the graphite alkyne-hyaluronic acid composite flame retardant, which comprises the steps of adding sulfydryl hyaluronic acid (HA-SH) and a reducing agent I into dispersion liquid of activated graphite alkyne (GDY-A), and carrying out sulfydryl-alkyne click reaction under the condition of an initiator to obtain graphite alkyne-hyaluronic acid composite flame retardant (GDY-HA);
the mass ratio of the activated graphdiyne to the thiolated hyaluronic acid is 1-5: 8-15;
the structural formula of the thiolated hyaluronic acid is as follows:
Figure BDA0003235694840000033
wherein R is
Figure BDA0003235694840000034
The carbonyl group in R is connected with the imino group, and X is
Figure BDA0003235694840000035
Figure BDA0003235694840000036
Figure BDA0003235694840000037
Wherein Δ represents a terminal bonded to the S atom, and represents a terminal bonded to the carbonyl group in R, and Y represents H or-NH 2 、-COOH、-CH 3 or-SH; the value range of m + n is 53-7890, and m and n are positive integers;
the activated graphdine is obtained by activating graphdine, and the activation means that the graphdine forms defects by etching under the catalysis condition, so that the activated alkynyl is exposed and can react with thiolated hyaluronic acid more easily, and the activating treatment method comprises the following steps: firstly, nano Ni or nano Cu and graphite alkyne are subjected to H treatment at 300-500 DEG C 2 Treating for 10-15 min in an Ar atmosphere to remove surface impurities, heating to 800-1000 ℃, continuing to treat for 15-25 min, etching the graphite alkyne under the catalysis of nano Ni or nano Cu, and cooling to room temperature (25 ℃) to obtain activated graphite alkyne;
the rate of heating or cooling is 35-55 ℃/min;
the average grain diameter of the nano Ni or the nano Cu is 30-100 nm.
The invention aims to control the 'mercapto-alkyne' click reaction between the graphite alkyne and the hyaluronic acid modified by the mercapto compound to generate a three-dimensional cross-linked network structure, however, the graphite alkyne is difficult to directly click with the hyaluronic acid modified by the mercapto compound due to the chemical stability of the graphite alkyne, so the invention is used in H 2 Firstly removing impurities of nano Ni or nano Cu and graphyne in an Ar atmosphere, and etching the graphyne at the high temperature of 800-1000 ℃ under the catalysis of the nano Ni or the nano Cu so as to weaken the interaction of the Ni or the Cu and C atoms and break partial C-C bonds or-C-bonds to form defects, thereby improving the reaction activity of the graphyne.
The reaction equation of the graphite alkyne (GDY) to form defects under the catalysis of the nano Ni or the nano Cu is as follows:
Ni+GDY+H 2 →CH 4 +Ni；
Cu+GDY+H 2 →CH 4 +Cu。
the graphyne is in a (1-5) nm x (50-1000) nm nano flaky structure, and is yellow gray in color;
the structural formula of the graphdiyne is as follows:
Figure BDA0003235694840000041
the graphite alkyne-hyaluronic acid composite flame retardant is prepared through sulfydryl-alkyne click reaction, sulfydryl-hyaluronic acid can be successfully bonded with graphite alkyne through infrared spectrum representation, and HA-SH infrared absorption peaks which are 1 more than HA (hyaluronic acid) are obtained from the spectrum, namely the peak is 2550-2590 cm -1 The stretching vibration peak of (2). At 1740-1750 cm -l And especially 1300cm -1 A strong fatty lipid C ═ O stretching peak appears, which indicates that after the esterification reaction, the sulfhydryl is connected to HA; compared with a GDY map, the test result of the graphite alkyne-hyaluronic acid composite flame retardant (GDY-HA) is that the peak is 1629-1635 cm except for the vibration absorption peak of a benzene ring framework -1 Infrared absorption with C-bondCollecting peaks, wherein the peaks are newly generated C ═ C bonds in products of the 'sulfydryl-alkyne' click reaction, and the peaks are at 2500-2560 cm -1 At and 980cm -1 Absorption peaks of sulfydryl (-SH) and C-S bonds are respectively increased, which shows that the sulfydryl hyaluronic acid is successfully connected to the graphdiyne.
As a preferred technical scheme:
in the method, the dispersion liquid of the activated graphdiyne is obtained by dispersing the activated graphdiyne in the solvent I and uniformly stirring; the solvent I is a mixed solution of ethanol and OP-10 or triton X-100, and the volume ratio of the ethanol to the OP-10 or triton X-100 in the mixed solution is 10: 1; the mass volume ratio of the activated graphdiyne to the solvent I is 0.1-0.5 g: 20-60 mL;
the reducing agent I is more than one of tri (2-carboxyethyl) phosphine, tri (2-formylethyl) phosphine hydrochloride (TCEP), dithiothreitol and 2-mercaptoethanol; the addition amount of the reducing agent I is 0.1-0.5% of the mass of the activated graphite alkyne, and the addition of the reducing agent I aims to ensure that the sulfhydrylation hyaluronic acid is not oxidized in the sulfydryl-alkyne click reaction;
the initiator is 4-Dimethylaminopyridine (DMAP) or Azobisisobutyronitrile (AIBN), and the addition amount of the initiator is 0.1-0.5% of the mass of the activated graphdine; when the initiator is 4-dimethylaminopyridine, the click reaction is performed under the conditions of irradiation of Ultraviolet (UV) light by an ultraviolet irradiator and light intensity of 10mW/cm 2 The irradiation time is 1-15 s; when the initiator is azobisisobutyronitrile, the click reaction is carried out at 70 ℃ for 0.5-5 min.
Method as described above, H 2 The gas flow ratio of the/Ar atmosphere is H 2 When the flow rate is 800:200sccm, sccm represents 273.15K, 100kPa and the flow rate unit mL/min;
the mass ratio of the nano Ni or the nano Cu to the graphite alkyne is 0.1-1: 1.
The preparation method of the thiolated hyaluronic acid comprises the following steps: to aminated hyaluronic acid (HA-NH) 2 ) Adding sulfhydryl compound and acetic anhydride (Ac) 2 O) and a reducing agent II, adding acetic acid to adjust the pH value to 4-5, and then placing the mixture in a constant temperature oscillator (the temperature of the constant temperature oscillator is set to be 30 ℃) for oscillationStanding for 1-5 h, then washing with a solvent II to be neutral, dialyzing with a dialysis bag, and finally performing centrifugal separation and vacuum freeze drying to obtain a powdery solid, namely the sulfhydrylation hyaluronic acid; in the prior art, the hydroxyl site of hyaluronic acid or salt thereof reacts with a disulfide compound under the action of a catalyst or an activator to generate hyaluronic acid disulfide compound, and then the sulfhydryl compound is reduced to be sulfhydryl to obtain the sulfhydrylated hyaluronic acid, but the invention firstly changes the amido bond of hyaluronic acid leaving carbonyl into amino, and then the carboxyl of the hyaluronic acid site reacts with the carboxyl of the sulfhydryl compound to obtain the sulfhydrylated hyaluronic acid, compared with the prior art, because the reactivity of the reaction of the amino and the carboxyl is higher than the reactivity of the reaction of the hydroxyl and the carboxyl, the preparation method of the sulfhydrylated hyaluronic acid does not need a catalyst or an activator, the preparation method is simple, the reaction is rapid, and the sulfhydrylation rate of hyaluronic acid is high;
the ratio of the aminated hyaluronic acid, the sulfhydryl compound, the acetic anhydride and the reducing agent II is 0.4-0.8 g, 4-8 mL, 2-4 mL and 0.01-0.05 g;
the structural formula of the aminated hyaluronic acid is as follows:
Figure BDA0003235694840000051
in the formula, the value range of m + n is 53-7890, and m and n are positive integers;
the mercapto compound is one or more of thioglycolic acid, cysteine (also known as 2-amino-3-mercaptopropionic acid), mercaptosuccinic acid, 4-mercaptobutyric acid, 4-mercaptobenzoic acid, 4-mercaptophenylacetic acid, 3-mercaptobenzoic acid, 3-mercaptoisobutyric acid, 6-mercaptohexanoic acid and 2, 3-dimercaptosuccinic acid, preferably thioglycolic acid or cysteine;
the reducing agent II is more than one of tri (2-carboxyethyl) phosphine, tri (2-formylethyl) phosphine hydrochloride (TCEP), dithiothreitol and 2-mercaptoethanol.
As described above, the thiolation rate of the aminated hyaluronic acid is 1.47mmol/g or more, the method for measuring the thiolation rate is carried out according to the Ellman's reagent method, the principle of the measurement method by the Ellman's method: the free thiol reacts with 5,5' -dithiobis (2-nitrobenzoic acid) (DTNB) with color development, absorption at 412nm UV, according to Lambert-Beer law: a linear relationship between the absorbance (a) and the thiol concentration (c) was established where a is 13600 and b is 1cm, and the actual thiol concentration was obtained by measuring the absorbance. The calculation method of the sulfhydrylation rate comprises the following steps: the thiolated hyaluronic acid consists of a repeated disaccharide structure (hyaluronic acid is a repeated disaccharide structure consisting of D-glucuronic acid and N-acetylglucosamine), 5mg of thiolated hyaluronic acid is weighed and prepared into an aqueous solution with the concentration of 0.1g/L, the aqueous solution is mixed with excessive DTNB for reaction for 5min to generate a colored substance, and the absorbance (A) of the colored substance is measured at 412 nm. The amount (n) of the thiol substance contained in 1g of the product is n ═ A/ε b/0.1, the absorbance A values of the thiol-modified hyaluronic acid obtained by the present invention are all 2.0 or more, and the thiol-modification rate is 1.47mmol/g or more.
In the above process, the solvent II is distilled water or aqueous ammonia containing 25 wt.% NH 3 ·H 2 An aqueous solution of O; the dialysate used in the dialysis treatment is ultrapure water, the ultrapure water is replaced every 3h, the water replacement volume is 2L every time, and the dialysis time is 18h in total; cooling to below 4 ℃ after dialysis treatment for centrifugal separation, wherein the centrifugal rotation speed is 10000-12000 r/min, and the centrifugal time is 30 min; the temperature of vacuum freeze drying is-60 deg.C, and the vacuum degree is 100 Pa.
As described above, the preparation method of the aminated hyaluronic acid comprises the following steps: adding hyaluronic acid to HCl/CH 3 Dissolving hyaluronic acid in OH solution under stirring, heating to 80 deg.C in water bath, refluxing for 24 hr, washing with pyridine (Py), and adding acetic anhydride (Ac) 2 O) cleaning to neutral (pH is 7), drying in a vacuum drying oven, and converting acetylamino of hyaluronic acid into amino to obtain aminated hyaluronic acid;
HCl/CH 3 the mass fraction of HCl in the OH solution is 6 percent;
hyaluronic acid and HCl/CH 3 The proportion of the OH solution is 0.01-0.8 mmol: 5-15 mL;
the hyaluronic acid has an average molecular weight of 20-3000 kDa;
the drying temperature is 30-50 ℃.
The invention also provides the application of the graphite alkyne-hyaluronic acid composite flame retardant, and the flame-retardant composite material is prepared by mixing the graphite alkyne-hyaluronic acid composite flame retardant with a high polymer material;
the high polymer material is PA6, PA66, PET or PLA;
the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 1-6 wt% of the high polymer material.
As a preferred technical scheme:
the application is characterized in that the flame retardant grade of the flame retardant composite material is V-0 grade;
when the high polymer material is PA6, compared with the high polymer material, the limit oxygen index of the flame-retardant composite material is increased by 4-13.5%, and the carbon residue at 800 ℃ is increased by 3.7-14.93%; t of the flame-retardant composite material 5％ Is 398-418 ℃ and T 10％ Is 395.8-435 ℃ and T max 467 to 486 ℃, 79.2 to 88.8MPa of tensile strength, 91.5 to 108MPa of bending strength and 10.1 to 13.3kJ/m of notch impact strength 2 ；
When the high polymer material is PA66, compared with the high polymer material, the limit oxygen index of the flame-retardant composite material is increased by 5-12%, and the carbon residue at 800 ℃ is increased by 5.5-14.2%; t of the flame-retardant composite material 5％ At a temperature of 388-409.5 ℃ and T 10％ Is 411.2-426 ℃ and T max 455 to 478 ℃, tensile strength of 68.1 to 75.6MPa, bending strength of 96 to 104.6MPa, and notch impact strength of 7.3 to 10.8kJ/m 2 ；
When the high polymer material is PET, compared with the high polymer material, the limit oxygen index of the flame-retardant composite material is increased by 5.3-13%, and the carbon residue at 800 ℃ is increased by 0.87-23.7%; t of the flame-retardant composite material 5％ Is 399 to 418 ℃ and T 10％ Is 420 to 431.5 ℃ and T max 426 to 439.0 ℃, tensile strength of 68.5 to 76.7MPa, bending strength of 83.2 to 98.6MPa, and notch impact strength of 8.7 to 13.5kJ/m 2 ；
When the polymer material is PLA, the polymer material is modified with the polymerCompared with a molecular material, the limit oxygen index of the flame-retardant composite material is increased by 6.5-13.7%, and the carbon residue at 800 ℃ is increased by 4.47-15.5%; t of the flame-retardant composite material 5％ Is 349-354 ℃ and T 10％ 374 to 378 ℃ and T max 384.9 to 405.5 ℃, the tensile strength is 60 to 79.3MPa, the bending strength is 88.4 to 97.5MPa, and the notch impact strength is 8.1 to 10.3kJ/m 2 。
The mechanism of the invention is as follows:
hyaluronic acid (also called hyaluronic acid, abbreviated as HA) is a high molecular polymer formed by repeating connection of disaccharide units consisting of D-glucuronic acid and N-acetylglucosamine, HAs excellent moisture retention, lubricity, viscoelasticity and biocompatibility, and is widely applied to the fields of medicines, cosmetics, foods and the like. The hyaluronic acid molecules contain a large amount of hydroxyl, amino, acetamido and other active groups, the hyaluronic acid can play a role in flame retardance of a carbon source and an air source during combustion, and the biocompatibility of the hyaluronic acid is good, so that the hyaluronic acid is expected to be used as a bio-based flame retardant to solve the problems of poor dispersibility, easy agglomeration and poor compatibility with high polymer materials of flame retardant nanoparticles to cause reduction of mechanical properties.
Graphyne (GDY) is sp 2 The carbon allotrope is formed by hybridization type carbon (on a benzene ring) and sp hybridization type carbon (on an alkyne bond), and is a two-dimensional plane network structure formed by conjugation connection of a 1, 3-diyne bond and the benzene ring. GDY has abundant carbon chemical bonds, large conjugated system, wide surface distance, excellent chemical stability, thermal stability and semiconductor performance, and can be widely used in energy, electron, information technology, catalysis, photoelectricity, etc. GDY has the characteristics of light weight, rigidity, loose porous structure and excellent thermal stability, and is expected to solve the problems of poor thermal stability and low carbon residue rate of the flame retardant in the prior art. However, if the graphdiyne is used for flame retardance, the nanoscale graphdiyne is easy to agglomerate and difficult to disperse, and the graphdiyne has no active functional group and is poor in compatibility with a polymer matrix, so that the mechanical property of the obtained material is poor, and the graphdiyne has no report of being applied to the flame retardant field.
The invention designs and constructs a novel composite flame retardant (GDY-HA) with a cross-linked net structure by carrying out 'mercapto-alkyne' click reaction on graphite alkyne and hyaluronic acid modified by a mercapto compound. In general, the stability of the sulfhydrylation polymer is poor, free sulfhydryls are easily oxidized into disulfide bonds slowly, and modification of hyaluronic acid by using a sulfhydrylation compound changes the rheological property of the obtained sulfhydrylation compound modified hyaluronic acid, so that the viscosity is increased, the flowing property is increased due to the increase of the viscosity, the bonding with the graphite alkyne is difficult, and the dispersion of the graphite alkyne is not facilitated. The graphdiyne contains a large number of sp hybridized carbon atoms, has strong electron deficiency characteristics and shows remarkable electron obtaining capacity, the graphdiyne can play a role in inhibiting or slowing down the oxidation of the graphdiyne, and the graphdiyne and the reducing agent are added with a small amount of reducing agent to cooperatively inhibit the conversion of mercapto groups to disulfide bonds, so that the stability of mercapto compounds can be ensured.
Through the cross-linking effect of the hyaluronic acid and the graphite alkyne, the porous laminar rigid structure of the graphite alkyne can protect the hyaluronic acid, and the graphite alkyne also has better dispersibility, so that the defects of instability and easy degradation of independently doped hyaluronic acid and poor compatibility with a polymer matrix due to the fact that the graphite alkyne is independently used and is easy to agglomerate are overcome. The hydrophilic hyaluronic acid and the hydrophobic graphite alkyne are combined to form a cross-linked network structure, the structure can be intertwined with a polymer matrix material chain, the compatibility with the polymer material is effectively improved, the graphite alkyne and the hyaluronic acid are mutually synergistic to form a supporting carbon layer, the carbon residue rate is improved, the heat transfer and the oxygen permeation are shielded, and the flammability of the polymer matrix material is reduced. When the doping amount of GDY-HA is not higher than 6%, the Limiting Oxygen Index (LOI) can reach 36%, the flame retardant rating is UL 94V-0, and the carbon residue rate is as high as 23.7%. Compared with the prior art, the composite flame retardant (GDY-HA) provided by the invention HAs the advantages of small doping amount, high flame retardant effect, good thermal stability, high carbon residue rate, environmental friendliness and the like. In addition, the composite flame retardant disclosed by the invention is applied to a high polymer material, has the effects of electromagnetic shielding, moisture preservation, lubrication, skin friendliness and the like, and has the electromagnetic shielding property because the conductivity of the graphite alkyne is 2.52 multiplied by 10 -4 S·m -1 And having loose porous knotsIn the preparation of the composite material by the graphite alkyne and the high molecular polymer matrix, the graphite alkyne can form a three-dimensional porous conductive network, when the content of the graphite alkyne is 5.0 wt.% of the polymer matrix material, the shielding efficiency of the composite material in the range of 8-12 GHz is 20-35 dB (the shielding efficiency is obtained by testing according to GJB 6190-2008 electromagnetic shielding material shielding effectiveness test method), the shielding mainly absorbs microwaves, and the reason for absorbing the microwaves is that the conductive network is formed; has the functions of moisturizing, lubricating and skin caring, mainly because hyaluronic acid contains hydroxyl, and has the characteristics of moisturizing and lubricating.
Has the advantages that:
(1) the invention relates to a preparation method of a graphite alkyne-hyaluronic acid composite flame retardant, which is a novel composite flame retardant with a cross-linked net structure designed and constructed by carrying out thiol-alkyne click reaction on graphite alkyne and hyaluronic acid modified by a thiol compound. The graphite alkyne lamellar structure can play a role in protecting hyaluronic acid, and simultaneously, the graphite alkyne can obtain better dispersity due to the generation of a new compound by crosslinking with hyaluronic acid, so that the defects of instability, easy degradation and the like in the process of independently doping hyaluronic acid and the defects of easy agglomeration and poor compatibility with a polymer matrix when the graphite alkyne nanosheet is independently used are overcome.
(2) The invention relates to a preparation method of a graphite alkyne-hyaluronic acid composite flame retardant, which is characterized in that the flame retardant with a cross-linked net structure generated by the 'mercapto-alkyne' click reaction between graphite alkyne and hyaluronic acid modified by a mercapto compound can be entangled with a polymer substrate material chain, so that a continuous and compact supporting carbon layer can be formed, the strength of the carbon layer is increased, the carbon layer generated at high temperature is not easy to collapse and crack, and the effects of shielding heat transfer and oxygen permeation are achieved, thereby effectively inhibiting heat release and reducing the flammability of the substrate materials such as polymers; in addition, the flame retardant contains N, S flame retardant elements, N element forms nitrogen-containing non-combustible gas by heating, combustion-supporting and combustible gas is diluted and is covered around the polymer to form a protective gas layer for isolating oxygen, and S element forms free radical by heating and can be combined with-C [ identical to ] C-of graphyne to form C-S bond (at 980 cm) -1 Infrared absorption peak) enters pores of graphate to form more uniform graphite alkyneThe dense net structure promotes the increase of the carbon residue and the strength of the carbon layer, and can play a role in shielding and blocking heat and smoke on flammable materials, and N, S flame retardant elements and graphite alkyne cooperatively play a flame retardant role; moreover, hyaluronic acid has strong water absorption, which is comparable to a water reservoir, can release water vapor by heating, can continuously release water absorbed by hyaluronic acid from air in the form of water vapor at high temperature, and the water vapor is used for diluting oxygen together with N-containing gas generated in the combustion process, and forms a protective layer on the surface of a high polymer, and the water vapor also has a heat absorption effect, can cover the surface of flame and isolate O 2 Flame retardance is achieved.
(3) The invention relates to a preparation method of a graphite alkyne-hyaluronic acid composite flame retardant, which is characterized in that due to the chemical stability of graphite alkyne, the graphite alkyne directly carries out click reaction with hyaluronic acid modified by a sulfhydryl compound 2 Etching the graphyne in the/Ar atmosphere to weaken the interaction between Ni or Cu and C atoms and break partial C-C bonds or-C-bond to form defects, thereby improving the reaction activity of the graphyne.
(4) The novel flame retardant prepared by the invention can be applied to the preparation of flame-retardant composite materials by mixing with high polymer materials, the LOI value can reach 36% under the condition that the doping amount is not higher than 6 wt.%, and the carbon residue rate can reach 23.7% through UL 94V-0 level. In addition, the flame retardant also has additional functions of antibiosis, moisture retention, electromagnetic shielding and the like, and can be used as an additive to be mixed with a high polymer material to obtain a composite material with good flame retardant property, mechanical property and electromagnetic shielding function.
Detailed Description
The present invention will be further described with reference to the following embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
The reagents used in the invention are all commercial products unless otherwise specified;
the graphdine in the invention is a commercial product purchased from Nanjing pioneer nanomaterial science and technology Limited;
the hyaluronic acid in the present invention is commercially available from west asia chemical technology limited.
The sulfhydrylation rate test method of the invention is carried out according to an Ellman reagent method;
in the invention, the Limiting Oxygen Index (LOI) is tested according to GB/T2406-93, a sample is vertically arranged on a sample clamp during testing, mixed gas of oxygen and nitrogen is introduced from the bottom of a combustion cylinder, an igniter ignites the sample from the upper end, and the oxygen concentration in the mixed gas is changed until the flame front just reaches the marked line of the sample. The main test methods are as follows: firstly, a standard sample strip (the specification of the sample strip is 100mm multiplied by 6.5mm multiplied by 3mm) with marked scale marks is vertically arranged on a sample clamp, mixed gas of oxygen and nitrogen is introduced from the bottom of a combustion cylinder, an igniter is used for igniting the sample from the upper end, and the oxygen concentration in the mixed gas is adjusted until the flame front just reaches the marked line of the sample. The LOI of the material was thus calculated and the arithmetic mean of the results of 3 experiments was taken as the measured value;
in the invention, the UL94 vertical burning test is carried out according to GB/T2406-2008, and the test sample vertical burning performance test is suitable for the determination of the plastic surface flame propagation test. Regularly burning a vertically placed sample strip (the specification is 125mm multiplied by 13mm multiplied by 3mm) for a plurality of times (more than 5 times) according to a certain flame height, and evaluating the combustibility according to the ignition duration of the sample and the ignition of an igniter laid under the sample;
the mechanical property test comprises a tensile property test, a bending property test and an impact property test, wherein the tensile property test is carried out according to ISO527-21-2012 standard, and the horizontal part of the sample is 80mm multiplied by 10mm multiplied by 4 mm; the bending property test is carried out according to ISO 178-2010, and the sample size is 80mm multiplied by 10mm multiplied by 4 mm; the impact performance test is carried out according to the ISO 179-2010 standard, and the sample size is 80mm multiplied by 10mm multiplied by 4 mm;
thermogravimetric analysis test in the invention: measured by SDT Q600(TA Co., Ltd.) of American company, about 5mg of sample is placed in a thermogravimetric analyzer under nitrogen atmosphere, the heating rate is 10 ℃/min, and the temperature range isMeasuring all samples repeatedly for 3 times at the temperature of 30-800 ℃, and taking an average value to ensure that the temperature error is +/-2 ℃ and the mass error is +/-2%; wherein, T 5％ Is the temperature at which the sample lost 5% weight, T 10％ Is the temperature at which the sample lost 10% weight, T max Is the fastest decomposition temperature, R, of the sample 800 Is the amount of residue of the sample at 800 ℃.
Example 1
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 492kDa is added to HCl/CH 3 In the OH solution, controlling the proportion relation between the two to be 0.8mmol:10mL, stirring and dissolving, heating in a water bath to 80 ℃, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 50 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding thioglycolic acid, acetic anhydride and tris (2-carboxyethyl) phosphine into aminated hyaluronic acid, wherein the ratio relation of the aminated hyaluronic acid, the thioglycolic acid, the acetic anhydride and the tris (2-carboxyethyl) phosphine is 0.6g:5mL:4mL:0.05g, adding acetic acid to adjust the pH value to 5, placing the mixture in a constant temperature oscillator to oscillate for 5 hours, then placing the mixture for 12 hours, washing the mixture with distilled water to be neutral, dialyzing the mixture by using a dialysis bag (the dialyzate used in the dialysis treatment is ultrapure water, the ultrapure water is replaced every 3 hours, the water volume is 2L each time, the dialysis time is 18 hours in total), cooling the mixture to-3 ℃ after the dialysis treatment to carry out centrifugal separation (the centrifugal rotation speed is 10000r/min, the centrifugal time is 30min), and finally carrying out vacuum freeze drying (the vacuum freeze drying temperature is-60 ℃ and the vacuum degree is 100Pa), obtaining powdery solid, namely sulfhydrylation hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.813 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Ni (with the average particle size of 30nm) and graphite alkyne in the mass ratio of 1:1 are mixed at 300 ℃ in the presence of H 2 an/Ar atmosphere (H 2 Gas flow ratio of/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 800 ℃ at the speed of 35 ℃/min, continuing to process for 25min, cooling to room temperature at the speed of 35 ℃/min to obtain activated graphite alkyne, dispersing the activated graphite alkyne in a mixed solution of ethanol and OP-10 (the volume ratio of the ethanol to the OP-10 in the mixed solution is 10:1), uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne, wherein the mass volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the OP-10 is 0.1g:20 mL;
(4) adding the thiolated hyaluronic acid and the tris (2-carboxyethyl) phosphine prepared in the step (2) into the dispersion liquid of the activated graphdine prepared in the step (3), and using light intensity of 10mW/cm under the condition of 4-dimethylaminopyridine 2 Irradiating the graphite alkyne-hyaluronic acid composite flame retardant for 1s by using UV light to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdiyne to the thiolated hyaluronic acid is 3:10, the addition amount of the tris (2-carboxyethyl) phosphine is 0.3% of the mass of the activated graphdiyne, and the addition amount of the 4-dimethylaminopyridine is 0.5% of the mass of the activated graphdiyne.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000111
wherein, m equals 874, n equals 347;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PA66, wherein the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 6 wt% of PA 66; the limit oxygen index of the prepared flame-retardant composite material is 36 percent, the flame-retardant grades are V-0 grade and T 5％ At 409.5 ℃ C, T 10％ At 426 ℃ and T max Is 478 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 23.7 percent; the tensile strength of the flame-retardant composite material is 75.6MPa, the bending strength is 104.6MPa, and the notch impact strength is 10.8kJ/m 2 。
Comparative example 1
Mixing Melamine Cyanurate (MCA) powder (average particle size is 5 mu m) serving as a flame retardant with PA66 to prepare the flame-retardant composite material, and the method for preparing the flame-retardant composite material is the same as the methodExample 1 and the amount of flame retardant added was also 6 wt.% of PA66, the ultimate oxygen index of the resulting flame retardant composite was 28.5%, T 5％ At 385.5 ℃ C, T 10％ At 390.3 ℃ and T max 468 ℃ is adopted; the residual carbon content of the flame-retardant composite material at 800 ℃ is 5.57 percent; the tensile strength of the flame-retardant composite material is 68.5MPa, the bending strength is 90.4MPa, and the notch impact strength is 5.8kJ/m 2 。
Comparing example 1 with comparative example 1, it can be seen that the limiting oxygen index of the flame-retardant composite material obtained in example 1 is improved by 26.3%, and T is increased by 5％ Increase by 6.2% and T 10％ Increase by 9.2% and T max The flame retardant is improved by 2.1 percent, the carbon residue of the flame-retardant composite material at 800 ℃ is increased by 10.43 percent, and the tensile strength, the bending strength and the notch impact strength of the flame-retardant composite material are respectively improved by 10.4 percent, 15.7 percent and 86 percent, because the MCA flame retardant in the comparative example 1 is in lamellar distribution in PA66, is easy to agglomerate and is easy to generate stress concentration, so that the mechanical property is not ideal; the MCA flame retardant mainly depends on cyanuric acid generated by thermal decomposition to cause the PA66 to be degraded, so that the heat is carried away to realize flame retardance, and the formed carbon layer has a plurality of holes on the surface, so that when the carbon layer with the structure is subjected to continuous heat, the heat can still be easily transferred to a polymer matrix, and the flame retardance of the carbon layer is inferior to that of the carbon layer in example 1. Compared with MCA flame retardant, the graphite alkyne-hyaluronic acid flame retardant in the embodiment 1 has better dispersibility in a polymer matrix and good compatibility with a polymer, and the graphite alkyne and hyaluronic acid have synergistic effect with each other to improve mechanical properties such as tensile strength, bending strength and notch impact strength; the graphite alkyne-hyaluronic acid flame retardant has a cross-linked network structure, a benzene ring and other rigid structures, a compact carbon layer is obtained after the formed flame-retardant composite material is combusted, the carbon residue rate is improved, the heat insulation and oxygen isolation effects are achieved, the flammability of PA66 is reduced, and T is caused 5％ 、T 10％ And T max The thermal stability of the flame-retardant composite material is improved when the thermal decomposition temperature is increased.
Example 2
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation ofAminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 1000kDa is added to HCl/CH 3 In the OH solution, controlling the proportion relation of the two to be 0.5mmol:15mL, stirring and dissolving, heating to 80 ℃ in a water bath, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 40 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding cysteine, acetic anhydride and tris (2-formylethyl) phosphine hydrochloride into aminated hyaluronic acid, wherein the proportion relation of the aminated hyaluronic acid, the cysteine, the acetic anhydride and the tris (2-formylethyl) phosphine hydrochloride is 0.6g:7mL:4mL:0.05g, adding acetic acid to adjust the pH value to 4, placing the mixture in a constant temperature oscillator to oscillate for 4 hours, then placing the mixture for 10 hours, washing the mixture to be neutral by 25 wt.% of ammonia water, dialyzing the mixture by using a dialysis bag (dialyzing solution is ultrapure water, the ultrapure water is replaced every 3 hours, the water volume is 2L each time, the dialysis time is 18 hours in total), cooling the dialyzed mixture to-2 ℃ to carry out centrifugal separation (the centrifugal rotating speed is 10000r/min, the centrifugal time is 30 minutes), and finally carrying out vacuum freeze drying (the vacuum freeze drying temperature is-60 ℃, the vacuum degree is 100Pa) to obtain powdery solid, namely the thiolated hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.796 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Ni (with the average particle size of 30nm) and graphite alkyne in the mass ratio of 0.9:1 are mixed at 300 ℃ in H 2 an/Ar atmosphere (H) 2 Gas flow ratio of/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 800 ℃ at the speed of 35 ℃/min, continuing to process for 25min, cooling to room temperature at the speed of 35 ℃/min to obtain activated graphite alkyne, dispersing the activated graphite alkyne in a mixed solution of ethanol and OP-10 (the volume ratio of the ethanol to the OP-10 in the mixed solution is 10:1), uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne, wherein the mass volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the OP-11 is 0.1g:25 mL;
(4) adding the sulfhydrylation hyaluronic acid and the tris (2-formylethyl) phosphine hydrochloride prepared in the step (2) into the dispersion liquid of the activated graphite alkyne prepared in the step (3), and heating for 0.5min at 70 ℃ under the condition of azodiisobutyronitrile to obtain a graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdine to the thiolated hyaluronic acid is 2:8, the addition amount of the tris (2-formylethyl) phosphine hydrochloride is 0.4% of the mass of the activated graphdine, and the addition amount of the azobisisobutyronitrile is 0.3% of the mass of the activated graphdine.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000131
wherein m is 1739, n is 613;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PA6, wherein the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 5 wt% of PA 6; the limit oxygen index of the prepared flame-retardant composite material is 33 percent, the flame-retardant grades are V-0 grade, and T is 5％ At 418 ℃ and T 10％ At 435 ℃ and T max Is 486 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 15 percent; the tensile strength of the flame-retardant composite material is 88.8MPa, the bending strength is 108MPa, and the notch impact strength is 13.3kJ/m 2 。
Comparative example 2
Mixing a 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) flame retardant with PA6 to prepare a flame-retardant composite material, wherein the method for preparing the flame-retardant composite material is the same as example 2, the addition amount of the flame retardant is 5 wt.% of PA6, and the T of the finally prepared flame-retardant composite material is 5％ At 382 ℃ and T max At 434 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 4.8 percent; tensile strength of 65.6MPa, bending strength of 59.5MPa and impact strength of 3.3kJ/m 2 。
As can be seen by comparing example 2 with comparative example 2, T of the flame-retardant composite obtained in example 2 5％ Increase by 9.4% and T max 12 percent of the carbon residue is increased, and the carbon residue of the flame-retardant composite material at 800℃ is increased10.2 percent, the tensile strength and the bending strength are respectively improved by 35.4 percent and 81.5 percent, and the notch impact strength is increased by 10kJ/m 2 . This is because the flame retardant in example 2 has a three-dimensional crosslinked network structure, has excellent thermal stability at high temperature, can form a dense carbon layer, and exhibits T max And the increase of the carbon residue rate, the flame retardant DOPO has a protective effect on a PA6 base material, while the flame retardant DOPO in the comparative example 2 has weak thermal stability even not as strong as that of pure PA6 (the influence of the ethyl bridge chain DOPO derivative on the flame retardant property of PA6, plastics science and technology, 2018, 46(11): 111) to cause T 5％ The value is not high, the flame-retardant composite material formed by DOPO is easy to thermally decompose when being burnt at high temperature, the formed carbon layer is not compact enough, and T is shown max Not as excellent as in example 2. The compatibility of DOPO and the polymer matrix is poor, stress concentration is easily formed in the polymer material, so that the bending strength of the polymer material is reduced by 83.1% (thermal degradation, flame retardance and mechanical properties of the DOPO derivative/polylactic acid composite material, 2021), compared with the flame retardant DOPO, the graphite alkyne-hyaluronic acid flame retardant in the embodiment 2 has better dispersibility in a polymer matrix and good compatibility with a polymer, an active functional group-OH on hyaluronic acid forms chemical bonding and physical van der Waals attraction with carboxyl or amino of PA6, and has better compatibility, the graphite alkyne has the characteristics of light weight and rigidity, and the mechanical properties of the flame retardant composite material can be enhanced, therefore, the graphite alkyne and the hyaluronic acid have synergistic effect with each other, and the mechanical properties such as tensile strength, bending strength and notch impact strength of the flame-retardant composite material are greatly improved.
Example 3
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 2000kDa was added to HCl/CH 3 In the OH solution, the proportion relation of the two is controlled to be 0.4mmol:12mL, stirring and dissolving are carried out, the temperature is heated to 80 ℃ in a water bath, then reflux is carried out for 24 hours, the obtained product is firstly washed by pyridine and then acetic anhydride to be neutral, and vacuum drying is carried outDrying in a drying box at the temperature of 35 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding 4-mercaptobutyric acid, acetic anhydride and dithiothreitol into aminated hyaluronic acid, wherein the proportion relationship of the aminated hyaluronic acid, the 4-mercaptobutyric acid, the acetic anhydride and the dithiothreitol is 0.6g:4mL: 0.04g, adding acetic acid to adjust the pH value to 4, then placing the mixture in a constant temperature oscillator to oscillate for 2h, then placing the mixture for 8h, washing the mixture with 25 wt.% ammonia water to be neutral, dialyzing the mixture by using a dialysis bag (dialyzate used in the dialysis treatment is ultrapure water, the ultrapure water is changed every 3h, the water volume is 2L every time, the dialysis time is 18h in total), cooling the dialyzed mixture to 0 ℃ to carry out centrifugal separation (the centrifugal rotating speed is 10000r/min, the centrifugal time is 30min), and finally carrying out vacuum freeze drying (the vacuum freeze drying temperature is-60 ℃, the vacuum degree is 100Pa) to obtain powdery solid, namely the thiolated hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.765 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Ni (with the average particle size of 50nm) and graphite alkyne in the mass ratio of 0.7:1 are mixed at 350 ℃ in H 2 an/Ar atmosphere (H) 2 Gas flow ratio of/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 1000 ℃ at the speed of 35 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, dispersing the activated graphite alkyne in a mixed solution of ethanol and OP-10 (the volume ratio of the ethanol to the OP-1 in the mixed solution is 10:1), uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne, wherein the mass volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the OP-13 is 0.3g:35 mL;
(4) adding the thiolated hyaluronic acid and dithiothreitol prepared in the step (2) into the dispersion liquid of the activated graphdine prepared in the step (3), and using light intensity of 10mW/cm under the condition of 4-dimethylaminopyridine 2 Irradiating the graphite alkyne-hyaluronic acid composite flame retardant for 5 seconds by using UV light to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphane to the thiolated hyaluronic acid is 4:11, the addition amount of dithiothreitol is 0.2 percent of the mass of the activated graphane, and the addition amount of 4-dimethylaminopyridine is the activated graphane0.2% of the mass.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000151
wherein, m is 3409, n is 1316;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PLA, wherein the adding amount of the graphite alkyne-hyaluronic acid composite flame retardant is 3 wt% of the PLA; the limit oxygen index of the prepared flame-retardant composite material is 33 percent, the flame-retardant grades are V-0 grade, and T is 5％ At 354 ℃ T 10％ At 378 ℃ T max 405.5 ℃ is adopted; the residual carbon content of the flame-retardant composite material at 800 ℃ is 15.5 percent; the tensile strength of the flame-retardant composite material is 79.3MPa, the bending strength is 97.5MPa, and the notch impact strength is 10.3kJ/m 2 。
Comparative example 3
Mixing a flame retardant compounded by triphenyl phosphate and montmorillonite in a mass ratio of 2:1 with PLA to prepare a flame-retardant composite material, wherein the method for preparing the flame-retardant composite material is the same as that in example 3, the addition amount of the flame retardant is 3 wt.% of the PLA, and the limit oxygen index of the finally prepared flame-retardant composite material is 33%; the tensile strength is 51.5MPa, the bending strength is 62.45MPa, and the impact strength is 6.02kJ/m 2 。
As can be seen from comparison of example 3 with comparative example 3, the tensile strength and the bending strength of the flame-retardant composite material obtained in example 3 are respectively improved by 54 percent and 56.1 percent, and the notched impact strength is improved by 4.28kJ/m 2 . The flame retardant is well combined with the polymer matrix due to good compatibility of the graphite alkyne-hyaluronic acid flame retardant and the polymer, and the active functional group on the hyaluronic acid and the PLA matrix form chemical bonding and physical van der Waals attraction, so that the flame retardant can be well dispersed in the PA6 matrix due to the crosslinking action of the graphite alkyne and the hyaluronic acid, the mechanical property of the flame retardant composite material can be enhanced due to the characteristics of light weight and rigidity of the graphite alkyne, and therefore, the tensile strength and the bending strength of the flame retardant composite material are greatly improved due to the synergistic action of the graphite alkyne and the hyaluronic acidBending strength, notch impact strength and other mechanical properties. Although the flame retardant compounded by the triphenyl phosphate and the montmorillonite has better flame retardant performance, the triphenyl phosphate cannot be well dispersed in a PLA matrix, and the mechanical properties of the flame retardant can be greatly influenced when more than 1% of triphenyl phosphate is added, so that the mechanical properties such as bending, stretching, notch impact strength and the like are reduced.
Example 4
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with the HCl mass fraction of 6% 3 An OH solution; hyaluronic acid with an average molecular weight of 200kDa is added to HCl/CH 3 In the OH solution, controlling the proportion relation of the two to be 0.01mmol:5mL, stirring and dissolving, heating in a water bath to 80 ℃, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 50 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding 4-mercaptobenzoic acid, acetic anhydride and dithiothreitol into aminated hyaluronic acid, wherein the ratio of aminated hyaluronic acid, 4-mercaptobenzoic acid, acetic anhydride and dithiothreitol is 0.7g:8mL:3mL:0.03g, adding acetic acid to adjust pH to 4, placing in a constant temperature oscillator to oscillate for 1h, then placing for 10h, washing with distilled water to neutrality, dialyzing with a dialysis bag (dialysate used for dialysis is ultrapure water, ultrapure water is replaced every 3h, the volume of water is 2L each time, the total dialysis time is 18h), cooling to 1 deg.C after dialysis treatment to carry out centrifugal separation (the centrifugal rotation speed is 12000r/min, the centrifugal time is 30min), and finally carrying out vacuum freeze drying (the vacuum freeze drying temperature is-60 deg.C, the vacuum degree is 100Pa) to obtain powdery solid, namely the thiolated hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.775 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Ni (with the average particle size of 50nm) and graphite alkyne in the mass ratio of 0.6:1 are mixed at the temperature of 500 ℃ in H 2 an/Ar atmosphere (H) 2 The gas flow ratio of the/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 1000 ℃ at the speed of 55 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, dispersing the activated graphite alkyne in a mixed solution of ethanol and OP-10 (the volume ratio of the ethanol to the OP-10 in the mixed solution is 10:1), uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne, wherein the mass volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the OP-14 is 0.4g:40 mL;
(4) adding the thiolated hyaluronic acid and dithiothreitol prepared in the step (2) into the dispersion liquid of the activated graphite alkyne prepared in the step (3), and heating for 2min at 70 ℃ under the condition of azodiisobutyronitrile to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdiyne to the thiolated hyaluronic acid is 5:9, the addition amount of dithiothreitol is 0.1% of the mass of the activated graphdiyne, and the addition amount of azobisisobutyronitrile is 0.2% of the mass of the activated graphdiyne.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000161
wherein, m is 342, n is 100;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PA66, wherein the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 3 wt% of PA 66; the limit oxygen index of the prepared flame-retardant composite material is 30 percent, the flame-retardant grades are V-0 grade, and T is 5％ At 394.6 ℃ C, T 10％ At 418.7 ℃ C, T max 459.3 ℃ is adopted; the residual carbon content of the flame-retardant composite material at 800 ℃ is 11.6 percent; the tensile strength of the flame-retardant composite material is 71.3MPa, the bending strength is 101.8MPa, and the notch impact strength is 8.6kJ/m 2 。
Example 5
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: taking a certain amount of hydrochloric acid andmixing the methanol to prepare HCl/CH with the HCl mass fraction of 6 percent 3 OH solution; hyaluronic acid with an average molecular weight of 800kDa is added to HCl/CH 3 In the OH solution, controlling the proportion relation of the two to be 0.3mmol:8mL, stirring and dissolving, heating to 80 ℃ in a water bath, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 30 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding 4-mercaptophenylacetic acid, acetic anhydride and dithiothreitol into aminated hyaluronic acid, wherein the proportion relation of the aminated hyaluronic acid, the 4-mercaptophenylacetic acid, the acetic anhydride and the dithiothreitol is 0.4g:7mL:3mL:0.03g, adding acetic acid to adjust the pH value to 4, then placing the mixture in a constant temperature oscillator to oscillate for 5h, then placing the mixture for 11h, washing the mixture to be neutral by 25 wt.% of ammonia water, dialyzing the mixture by using a dialysis bag (a dialyzate used in the dialysis treatment is ultrapure water, the ultrapure water is replaced every 3h, the water volume is 2L each time, the dialysis time is 18h in total), cooling the dialyzed mixture to 2 ℃ for centrifugal separation (the centrifugal rotation speed is 10000r/min, the centrifugal time is 30min), and finally performing vacuum freeze drying (the vacuum freeze drying temperature is-60 ℃ and the vacuum degree is 100Pa), obtaining powdery solid, namely thiolated hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.802 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Cu (with the average particle size of 60nm) and graphite alkyne in the mass ratio of 0.5:1 are mixed at the temperature of 500 ℃ in H 2 /Ar atmosphere (H) 2 The gas flow ratio of the/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 1000 ℃ at the speed of 55 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, finally dispersing the activated graphite alkyne in a mixed solution of ethanol and triton X-100 (the volume ratio of the ethanol to the triton X-100 in the mixed solution is 10:1), wherein the mass-to-volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the triton X-100 is 0.4g:50mL, and uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne;
(4) adding the thiolated hyaluronic acid and dithiothreitol prepared in the step (2) into the dispersion liquid of the activated graphdiyne prepared in the step (3), and heating for 5min at 70 ℃ under the condition of azodiisobutyronitrile to obtain the graphdiyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdiyne to the thiolated hyaluronic acid is 2:9, the addition amount of dithiothreitol is 0.3% of the mass of the activated graphdiyne, and the addition amount of azobisisobutyronitrile is 0.3% of the mass of the activated graphdiyne.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000181
wherein, m is 1393, n is 316;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PA6, wherein the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 3 wt% of PA 6; the limit oxygen index of the prepared flame-retardant composite material is 31 percent, the flame-retardant grades are V-0 grade, and T is 5％ At 404.8 ℃ C, T 10％ At 422.5 ℃ and T max 477.4 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 12.7 percent; the tensile strength of the flame-retardant composite material is 80.5MPa, the bending strength is 93.7MPa, and the notch impact strength is 15.1kJ/m 2 。
Example 6
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with the HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 1599kDa was added to HCl/CH 3 In the OH solution, controlling the proportion relation between the two to be 0.7mmol:15mL, stirring and dissolving, heating in a water bath to 80 ℃, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 45 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding 3-mercaptobenzoic acid, acetic anhydride and 2-mercaptoethanol into aminated hyaluronic acid, wherein the ratio of aminated hyaluronic acid to 3-mercaptobenzoic acid to acetic anhydride to 2-mercaptoethanol is 0.5g:7mL:4mL:0.02g, adding acetic acid to adjust pH to 5, placing in a constant temperature oscillator to oscillate for 4h, then placing for 12h, washing with distilled water to neutrality, dialyzing with a dialysis bag (dialyzing solution is ultrapure water, ultrapure water is replaced every 3h, the volume of water is 2L every time, the total dialysis time is 18h), cooling to 2 ℃ after dialysis treatment for centrifugal separation (the centrifugal rotation speed is 10000r/min, the centrifugal time is 30min), and finally performing vacuum freeze drying (the temperature of vacuum freeze drying is-60 ℃, the vacuum degree is 100Pa), obtaining powdery solid, namely sulfhydrylation hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.719 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Cu (with the average particle size of 80nm) and graphite alkyne in the mass ratio of 0.4:1 are mixed at 500 ℃ in H 2 an/Ar atmosphere (H) 2 The gas flow ratio of the/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 1000 ℃ at the speed of 55 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, finally dispersing the activated graphite alkyne in a mixed solution of ethanol and triton X-100 (the volume ratio of the ethanol to the triton X-100 in the mixed solution is 10:1), wherein the mass-to-volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the triton X-101 is 0.1g:60mL, and uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne;
(4) adding the thiolated hyaluronic acid and 2-mercaptoethanol prepared in the step (2) into the dispersion liquid of the activated graphdine prepared in the step (3), and using light intensity of 10mW/cm under the condition of 4-dimethylaminopyridine 2 Irradiating the graphite alkyne-hyaluronic acid composite flame retardant for 15 seconds by using UV light to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphitic alkyne to the thiolated hyaluronic acid is 3:15, the addition amount of the 2-mercaptoethanol is 0.4 percent of the mass of the activated graphitic alkyne, and the addition amount of the 4-dimethylaminopyridine is 0.3 percent of the mass of the activated graphitic alkyne.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000191
wherein m is 2629, n is 929;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PET, wherein the adding amount of the graphite alkyne-hyaluronic acid composite flame retardant is 2.5 wt% of the PET; the limit oxygen index of the prepared flame-retardant composite material is 28 percent, the flame-retardant grades are V-0 grade, and T is 5％ 399 ℃ C, T 10％ At 420 ℃ and T max At 426 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 13 percent; the tensile strength of the flame-retardant composite material is 68.5MPa, the bending strength is 83.2MPa, and the notch impact strength is 8.7kJ/m 2 。
Comparative example 4
Preparing a graphene oxide/carboxylated carbon nanotube according to a method of 'GO/MWCNT-COOH/PET composite material preparation and performance, 2020' in a literature, obtaining a flame retardant according to a mass ratio of the graphene oxide to the carboxylated carbon nanotube of 2:3, then mixing the flame retardant and PET to prepare a flame-retardant composite material, wherein the method for preparing the flame-retardant composite material is the same as that in example 6, the addition amount of the flame retardant is 2.5 wt.% of the PET, and the ultimate oxygen index of the finally prepared flame-retardant composite material is 26.5%; tensile strength is 68.2MPa, and bending strength is 82.5 MPa.
Comparing example 6 with comparative example 4, it can be seen that the limiting oxygen index of the flame retardant composite obtained in example 6 is increased by 5.7%, and the tensile strength and bending strength are comparable to the same. This is because the hyaluronic acid in the flame retardant in example 6 and the graphite alkyne form a dense cross-linked network structure, which can effectively inhibit the combustion of the polylactic acid, and although the flame retardant in comparative example 4 can exert a shielding effect to a certain extent, the shielding effect is difficult to continuously resist the combustion of the substrate, the hyaluronic acid has an effect of absorbing the surface heat of the polymer substrate, and can also cooperate with the graphite alkyne to form a polymer protective layer, which inhibits the heat release and reduces the flammability of the polylactic acid substrate. Even though the fire retardant GO/MWCNT-COOH in the comparative example 4 can improve the mechanical property of the polylactic acid, when the addition amount is 2.5%, agglomeration occurs, so that the stress concentration occurs due to uneven dispersion in a polymer matrix, and the mechanical property is similar to that of the example 6, while the agglomeration problem caused by the increase of the addition amount of the fire retardant is reduced to a certain extent by the crosslinking effect of the graphite alkyne and the hyaluronic acid in the example 6.
Example 7
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 2500kDa was added to HCl/CH 3 In the OH solution, controlling the proportion relation between the two to be 0.2mmol:6mL, stirring and dissolving, heating in a water bath to 80 ℃, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 50 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding 3-mercaptoisobutyric acid, acetic anhydride and tris (2-formylethyl) phosphine hydrochloride into aminated hyaluronic acid, wherein the proportion relationship of the aminated hyaluronic acid, the 3-mercaptoisobutyric acid, the acetic anhydride and the tris (2-formylethyl) phosphine hydrochloride is 0.8g:7mL:4mL:0.02g, adding acetic acid to adjust the pH value to 5, placing the mixture in a constant-temperature oscillator to oscillate for 3 hours, then placing the mixture for 10 hours, washing the mixture with 25 wt.% of ammonia water to be neutral, carrying out dialysis treatment by using a dialysis bag (the dialysate used for the dialysis treatment is ultrapure water, the ultrapure water is changed every 3 hours, the water volume is changed every time and the dialysis time is totally 18 hours), cooling the mixture to 3 ℃ after the dialysis treatment, carrying out centrifugal separation (the centrifugal rotation speed is 10000r/min and the centrifugal time is 30min), and finally carrying out vacuum freeze drying (the temperature of vacuum freeze drying is-60 ℃, the vacuum degree is 100Pa) to obtain powdery solid, namely the thiolated hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.606 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Cu (with the average particle size of 100nm) and graphite alkyne in the mass ratio of 0.3:1 are mixed at the temperature of 500 ℃ in H 2 an/Ar atmosphere (H) 2 Gas flow ratio of/Ar atmosphere is H 2 /Ar＝800:200sccm) for 10min, heating to 1000 ℃ at the speed of 55 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, dispersing the activated graphite alkyne in a mixed solution of ethanol and triton X-100 (the volume ratio of the ethanol to the triton X-100 in the mixed solution is 10:1), uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne, wherein the mass volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the triton X-102 is 0.2g:50 mL;
(4) adding the thiolated hyaluronic acid and the tris (2-formylethyl) phosphine hydrochloride prepared in the step (2) into the dispersion liquid of the activated graphdiyne prepared in the step (3), and using the light intensity of 10mW/cm under the condition of 4-dimethylamino pyridine 2 Irradiating the graphite alkyne-hyaluronic acid composite flame retardant for 15 seconds by using UV light to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdine to the thiolated hyaluronic acid is 4:8, the addition amount of the tris (2-formylethyl) phosphine hydrochloride is 0.5 percent of the mass of the activated graphdine, and the addition amount of the 4-dimethylaminopyridine is 0.3 percent of the mass of the activated graphdine.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000211
wherein, m is 3836, n is 2137;
preparing a flame-retardant composite material by adopting a melt blending method of the prepared graphite alkyne-hyaluronic acid composite flame retardant and PA66, wherein the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 1 wt% of PA 66; the limit oxygen index of the prepared flame-retardant composite material is 28 percent, the flame-retardant grades are V-0 grade and T 5％ At 388 ℃ C, T 10％ At 411.2 ℃ C, T max Is 455 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 9.8 percent; the tensile strength of the flame-retardant composite material is 68.1MPa, the bending strength is 96MPa, and the notch impact strength is 7.3kJ/m 2 。
Example 8
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: taking a certain amountMixing hydrochloric acid and methanol to prepare HCl/CH with HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 20kDa is added to HCl/CH 3 In the OH solution, controlling the proportion relation between the two to be 0.5mmol:5mL, stirring and dissolving, heating in a water bath to 80 ℃, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 30 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding 6-mercaptohexanoic acid, acetic anhydride and tris (2-formylethyl) phosphine hydrochloride into aminated hyaluronic acid, wherein the ratio of aminated hyaluronic acid, 6-mercaptohexanoic acid, acetic anhydride and tris (2-formylethyl) phosphine hydrochloride is 0.5g:6mL:4mL:0.01g, adding acetic acid to adjust pH to 5, placing in a constant temperature oscillator to oscillate for 2h, then placing for 9h, washing with distilled water to neutrality, dialyzing with a dialysis bag (dialyzing solution is ultrapure water, ultrapure water is replaced every 3h, water volume is 2L each time, dialysis time is 18h in total), cooling to 3 ℃ after dialysis, centrifuging (centrifugal rotation speed is 10000r/min, centrifugal time is 30min), and finally performing vacuum freeze drying (vacuum freeze drying temperature is-60 ℃, the vacuum degree is 100Pa) to obtain powdery solid, namely the thiolated hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.550 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Cu (with the average particle size of 50nm) and graphite alkyne in the mass ratio of 0.2:1 are mixed at 500 ℃ in H 2 an/Ar atmosphere (H) 2 The gas flow ratio of the/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 1000 ℃ at the speed of 55 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, finally dispersing the activated graphite alkyne in a mixed solution of ethanol and triton X-100 (the volume ratio of the ethanol to the triton X-100 in the mixed solution is 10:1), wherein the mass-to-volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the triton X-103 is 0.5g:30mL, and uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne;
(4) adding the sulfhydrylation hyaluronic acid and tris (2-formylethyl) phosphine hydrochloride prepared in the step (2) into the dispersion liquid of the activated graphite alkyne prepared in the step (3), and heating for 5min at 70 ℃ under the condition of azodiisobutyronitrile to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdine to the thiolated hyaluronic acid is 1:12, the addition amount of the tris (2-formylethyl) phosphine hydrochloride is 0.3% of the mass of the activated graphdine, and the addition amount of the azobisisobutyronitrile is 0.2% of the mass of the activated graphdine.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000221
wherein m is 30, n is 16;
preparing a flame-retardant composite material by adopting the prepared graphite alkyne-hyaluronic acid composite flame retardant and PLA in a melt blending method, wherein the adding amount of the graphite alkyne-hyaluronic acid composite flame retardant is 2.5 wt% of the PLA; the limit oxygen index of the prepared flame-retardant composite material is 27 percent, the flame-retardant grades are V-0 grade, and T is 5％ At 349 ℃ T 10％ At 374 ℃ T max At 384.9 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 6.8 percent; the tensile strength of the flame-retardant composite material is 60MPa, the bending strength is 88.4MPa, and the notch impact strength is 8.1kJ/m 2 。
Example 9
A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant comprises the following specific steps:
(1) preparation of aminated hyaluronic acid: mixing a certain amount of hydrochloric acid with methanol to prepare HCl/CH with the HCl mass fraction of 6% 3 OH solution; hyaluronic acid with an average molecular weight of 3000kDa was added to HCl/CH 3 In the OH solution, controlling the proportion relation of the two to be 0.1mmol:0.5mL, stirring and dissolving, heating in a water bath to 80 ℃, refluxing for 24 hours, washing the obtained product with pyridine, then washing with acetic anhydride to be neutral, putting the product into a vacuum drying oven, and drying at the temperature of 50 ℃ to obtain aminated hyaluronic acid;
(2) preparation of thiolated hyaluronic acid using aminated hyaluronic acid: adding thioglycolic acid, acetic anhydride and tris (2-carboxyethyl) phosphine into aminated hyaluronic acid, wherein the ratio relation of the aminated hyaluronic acid, the thioglycolic acid, the acetic anhydride and the tris (2-carboxyethyl) phosphine is 0.4g:5mL:4mL:0.04g, adding acetic acid to adjust the pH value to 5, placing the mixture in a constant temperature oscillator to oscillate for 3h, then placing the mixture for 9h, washing the mixture with distilled water to be neutral, dialyzing the mixture with a dialysis bag (the dialyzate used in the dialysis treatment is ultrapure water, the ultrapure water is replaced every 3h, the water volume is 2L each time, the dialysis time is 18h in total), cooling the mixture to-1 ℃ after dialysis treatment to carry out centrifugal separation (the centrifugal rotation speed is 10000r/min, the centrifugal time is 30min), and finally carrying out vacuum freeze drying (the vacuum freeze drying temperature is-60 ℃ and the vacuum degree is 100Pa), obtaining powdery solid, namely sulfhydrylation hyaluronic acid; wherein the sulfhydrylation rate of the aminated hyaluronic acid is 1.785 mmol/g;
(3) preparing a dispersion of activated graphdiyne: firstly, nano Ni (with the average particle size of 35nm) and graphite alkyne in the mass ratio of 0.8:1 are mixed at 350 ℃ in H 2 an/Ar atmosphere (H) 2 The gas flow ratio of the/Ar atmosphere is H 2 800/Ar: 200sccm), heating to 1000 ℃ at the speed of 35 ℃/min, continuing to process for 15min, cooling to room temperature at the speed of 55 ℃/min to obtain activated graphite alkyne, dispersing the activated graphite alkyne in a mixed solution of ethanol and OP-10 (the ratio of the ethanol to the OP-10 in the mixed solution is 10:1), uniformly stirring to obtain a dispersion liquid of the activated graphite alkyne, wherein the mass-to-volume ratio of the activated graphite alkyne to the mixed solution of the ethanol and the OP-10 is 0.2g:300 mL;
(4) adding the thiolated hyaluronic acid and the tris (2-carboxyethyl) phosphine prepared in the step (2) into the dispersion liquid of the activated graphdine prepared in the step (3), and using light intensity of 10mW/cm under the condition of 4-dimethylaminopyridine 2 Irradiating the graphite alkyne-hyaluronic acid composite flame retardant for 5 seconds by using UV light to obtain the graphite alkyne-hyaluronic acid composite flame retardant; wherein the mass ratio of the activated graphdiyne to the thiolated hyaluronic acid is 3:8, the addition amount of the tris (2-carboxyethyl) phosphine is 0.5% of the mass of the activated graphdiyne, and the addition amount of the 4-dimethylaminopyridine is 0.3% of the mass of the activated graphdiyne.
The structural formula of the finally prepared graphite alkyne-hyaluronic acid composite flame retardant is as follows:
Figure BDA0003235694840000231
wherein, m is 4286, n is 3247;
preparing a flame-retardant composite material by adopting the prepared graphite alkyne-hyaluronic acid composite flame retardant and PET by adopting a melt blending method, wherein the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 5 wt% of the PET; the limit oxygen index of the prepared flame-retardant composite material is 32 percent, the flame-retardant grades are V-0 grade, and T is 5％ At 413 ℃ T 10％ At 424.6 ℃ and T max Is 430 ℃; the residual carbon content of the flame-retardant composite material at 800 ℃ is 23.7 percent; the tensile strength of the flame-retardant composite material is 76.7MPa, the bending strength is 98.6MPa, and the notch impact strength is 13.5kJ/m 2 。
Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the invention as defined by the appended claims. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A graphite alkyne-hyaluronic acid composite flame retardant is characterized in that: the structural formula of the graphite alkyne-hyaluronic acid composite flame retardant is as follows;
Figure FDA0003235694830000011
wherein R is
Figure FDA0003235694830000012
The carbonyl group in R is connected with the imino group, and X is
Figure FDA0003235694830000013
Figure FDA0003235694830000014
Figure FDA0003235694830000015
Figure FDA0003235694830000016
Wherein Δ represents a terminal bonded to the S atom, and represents a terminal bonded to the carbonyl group in R, and Y represents H or-NH 2 、-COOH、-CH 3 or-SH; the value range of m + n is 53-7890, and m and n are positive integers.
2. A preparation method of a graphite alkyne-hyaluronic acid composite flame retardant is characterized by comprising the following steps: adding sulfhydrylation hyaluronic acid and a reducing agent I into dispersion liquid of activated graphite alkyne, and carrying out click reaction under the condition of an initiator to obtain a graphite alkyne-hyaluronic acid composite flame retardant;
the mass ratio of the activated graphdiyne to the thiolated hyaluronic acid is 1-5: 8-15;
the structural formula of the thiolated hyaluronic acid is as follows:
Figure FDA0003235694830000021
wherein R is
Figure FDA0003235694830000022
The carbonyl group in R is connected with the imino group, and X is
Figure FDA0003235694830000023
Figure FDA0003235694830000024
Figure FDA0003235694830000025
Wherein Δ represents the end attached to the S atom, and Δ represents the end attached to ROne end of the carbonyl group being attached, Y being H or-NH 2 、-COOH、-CH 3 or-SH; the value range of m + n is 53-7890, and m and n are both positive integers;
the activated graphdiyne is obtained by activating graphdiyne, and the activating treatment method comprises the following steps: firstly, nano Ni or nano Cu and graphite alkyne are subjected to H treatment at 300-500 DEG C 2 Treating for 10-15 min in Ar atmosphere, then heating to 800-1000 ℃, continuing to treat for 15-25 min, and then cooling to room temperature to obtain activated grapyne;
the rate of heating or cooling is 35-55 ℃/min;
the average grain diameter of the nano Ni or the nano Cu is 30-100 nm.
3. The method as claimed in claim 2, wherein the dispersion of activated graphdine is obtained by dispersing activated graphdine in solvent i and stirring it uniformly; the solvent I is a mixed solution of ethanol and OP-10 or triton X-100, and the volume ratio of the ethanol to the OP-10 or triton X-100 in the mixed solution is 10: 1; the mass volume ratio of the activated graphdiyne to the solvent I is 0.1-0.5 g: 20-60 mL;
the reducing agent I is more than one of tri (2-carboxyethyl) phosphine, tri (2-formylethyl) phosphine hydrochloride, dithiothreitol and 2-mercaptoethanol; the addition amount of the reducing agent I is 0.1-0.5% of the mass of the activated graphite alkyne;
the initiator is 4-dimethylamino pyridine or azodiisobutyronitrile, and the addition amount of the initiator is 0.1-0.5% of the mass of the activated graphite alkyne; when the initiator is 4-dimethylamino pyridine, the click reaction condition is UV light irradiation and the light intensity is 10mW/cm 2 The irradiation time is 1-15 s; when the initiator is azobisisobutyronitrile, the click reaction is carried out at 70 ℃ for 0.5-5 min.
4. The method of claim 2, wherein H is 2 The gas flow ratio of the/Ar atmosphere is H 2 800 parts by mass/Ar, 200 sccm; the mass ratio of the nano Ni or the nano Cu to the graphite alkyne is 0.1-1: 1.
5. The method according to claim 2, wherein the thiolated hyaluronic acid is prepared by: adding a sulfhydryl compound, acetic anhydride and a reducing agent II into aminated hyaluronic acid, adding acetic acid to adjust the pH value to 4-5, placing the mixture in a constant-temperature oscillator to oscillate for 1-5 hours, then placing the mixture for 8-12 hours, washing the mixture to be neutral by using a solvent II, performing dialysis treatment by using a dialysis bag, and finally performing centrifugal separation and vacuum freeze drying to obtain a powdery solid, namely the thiolated hyaluronic acid;
the ratio of the aminated hyaluronic acid, the sulfhydryl compound, the acetic anhydride and the reducing agent II is 0.4-0.8 g, 4-8 mL, 2-4 mL and 0.01-0.05 g;
the structural formula of the aminated hyaluronic acid is as follows:
Figure FDA0003235694830000031
in the formula, the value range of m + n is 53-7890, and m and n are positive integers;
the mercapto compound is more than one of thioglycolic acid, cysteine, mercaptosuccinic acid, 4-mercaptobutyric acid, 4-mercaptobenzoic acid, 4-mercaptophenylacetic acid, 3-mercaptobenzoic acid, 3-mercaptoisobutyric acid, 6-mercaptohexanoic acid and 2, 3-dimercaptosuccinic acid;
the reducing agent II is more than one of tri (2-carboxyethyl) phosphine, tri (2-formylethyl) phosphine hydrochloride, dithiothreitol and 2-mercaptoethanol.
6. The method according to claim 5, wherein the thiolation rate of the aminated hyaluronic acid is 1.47mmol/g or more.
7. The process according to claim 5, wherein the solvent II is distilled water or aqueous ammonia containing 25 wt.% NH 3 ·H 2 An aqueous solution of O; the dialysate used in the dialysis treatment is ultrapure water, the ultrapure water is replaced every 3h, the water replacement volume is 2L every time, and the dialysis time is 18h in total; cooling to below 4 ℃ after dialysis treatment for centrifugal separation at the rotating speed of 10000-12000 r/minThe time is 30 min; the temperature of vacuum freeze drying is-60 ℃, and the vacuum degree is 100 Pa.
8. The method according to claim 5, wherein the preparation of the aminated hyaluronic acid is: adding hyaluronic acid to HCl/CH 3 Dissolving in OH solution under stirring, heating to 80 ℃ in water bath, refluxing for 24h, washing the obtained product with pyridine, washing with acetic anhydride to neutrality, and drying in a vacuum drying oven to obtain aminated hyaluronic acid;
HCl/CH 3 the mass fraction of HCl in the OH solution is 6 percent;
hyaluronic acid and HCl/CH 3 The proportion of the OH solution is 0.01-0.8 mmol: 5-15 mL;
the hyaluronic acid has an average molecular weight of 20-3000 kDa;
the drying temperature is 30-50 ℃.
9. The application of the graphite alkyne-hyaluronic acid composite flame retardant of claim 1, wherein: mixing the graphite alkyne-hyaluronic acid composite flame retardant with a high polymer material to prepare a flame-retardant composite material;
the high polymer material is PA6, PA66, PET or PLA;
the addition amount of the graphite alkyne-hyaluronic acid composite flame retardant is 1-6 wt% of the high polymer material.
10. The use according to claim 9, wherein the flame retardant composite has a flame retardant rating of V-0;
when the high polymer material is PA6, compared with the high polymer material, the limit oxygen index of the flame-retardant composite material is increased by 4-13.5%, and the carbon residue at 800 ℃ is increased by 3.7-14.93%; t of the flame-retardant composite material 5％ 398 to 418 ℃ and T 10％ Is 395.8-435 ℃ and T max 467 to 486 ℃, 79.2 to 88.8MPa of tensile strength, 91.5 to 108MPa of bending strength and 10.1 to 13.3kJ/m of notch impact strength 2 ；
When the polymer material is PWhen A66 is adopted, compared with the high polymer material, the limit oxygen index of the flame-retardant composite material is increased by 5-12%, and the carbon residue at 800 ℃ is increased by 5.5-14.2%; t of the flame-retardant composite material 5％ At a temperature of 388-409.5 ℃ and T 10％ Is 411.2-426 ℃ and T max 455 to 478 ℃, tensile strength of 68.1 to 75.6MPa, bending strength of 96 to 104.6MPa, and notch impact strength of 7.3 to 10.8kJ/m 2 ；
When the high polymer material is PET, compared with the high polymer material, the limit oxygen index of the flame-retardant composite material is increased by 5.3-13%, and the carbon residue at 800 ℃ is increased by 0.87-23.7%; t of the flame-retardant composite material 5％ Is 399 to 418 ℃ and T 10％ At 420-431.5 ℃ and T max 426 to 439.0 ℃, tensile strength of 68.5 to 76.7MPa, bending strength of 83.2 to 98.6MPa, and notch impact strength of 8.7 to 13.5kJ/m 2 ；
When the high polymer material is PLA, compared with the high polymer material, the limiting oxygen index of the flame-retardant composite material is increased by 6.5-13.7%, and the carbon residue at 800 ℃ is increased by 4.47-15.5%; t of the flame-retardant composite material 5％ Is 349-354 ℃ and T 10％ 374 to 378 ℃ and T max 384.9 to 405.5 ℃, the tensile strength is 60 to 79.3MPa, the bending strength is 88.4 to 97.5MPa, and the notch impact strength is 8.1 to 10.3kJ/m 2 。
CN202111001160.4A 2021-08-30 2021-08-30 Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof Active CN113773513B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111001160.4A CN113773513B (en) 2021-08-30 2021-08-30 Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111001160.4A CN113773513B (en) 2021-08-30 2021-08-30 Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof

Publications (2)

Publication Number Publication Date
CN113773513A CN113773513A (en) 2021-12-10
CN113773513B true CN113773513B (en) 2022-08-23

Family

ID=78839854

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111001160.4A Active CN113773513B (en) 2021-08-30 2021-08-30 Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof

Country Status (1)

Country Link
CN (1) CN113773513B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116925375B (en) * 2023-07-18 2024-03-26 东莞市普万光电散热科技有限公司 Graphene oxide grafted modified polyamide composite material, fabric and preparation method thereof

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104248764A (en) * 2014-08-13 2014-12-31 东华大学 Preparation method of graphene oxide composite material modified by hyaluronic acid
CN105523547B (en) * 2016-01-25 2017-09-29 浙江大学 A kind of super flexible high heat conduction graphene film and preparation method thereof
CN112341804A (en) * 2020-10-27 2021-02-09 合肥通融新型材料科技有限公司 Preparation method of flame-retardant polyamide composite material

Also Published As

Publication number Publication date
CN113773513A (en) 2021-12-10

Similar Documents

Publication Publication Date Title
Zhang et al. Non-aromatic Si, P, N-containing hyperbranched flame retardant on reducing fire hazards of epoxy resin with desirable mechanical properties and lower curing temperature
Zhi et al. Thermal stability and flame retardancy properties of epoxy resin modified with functionalized graphene oxide containing phosphorus and silicon elements
Chu et al. Renewable vanillin-based flame retardant toughening agent with ultra-low phosphorus loading for the fabrication of high-performance epoxy thermoset
Wang et al. Preparation of cobalt-based metal organic framework and its application as synergistic flame retardant in thermoplastic polyurethane (TPU)
Yuan et al. Synthesis of a novel multi-structure synergistic POSS-GO-DOPO ternary graft flame retardant and its application in polypropylene
Yousefi et al. Polymeric nanocomposite materials: preparation and characterization of star-shaped PbS nanocrystals and their influence on the thermal stability of acrylonitrile–butadiene–styrene (ABS) copolymer
Wang et al. Preparation of silane precursor microencapsulated intumescent flame retardant and its enhancement on the properties of ethylene–vinyl acetate copolymer cable
Xia et al. Green construction of multi-functional fire resistant epoxy resins based on boron nitride with core-shell structure
CN111040293B (en) Intumescent flame-retardant polypropylene and preparation method thereof
Shi et al. A phosphorus/silicon-based, hyperbranched polymer for high-performance, fire-safe, transparent epoxy resins
Gao et al. Constructing segregated polystyrene composites for excellent fire resistance and electromagnetic wave shielding
Xiao et al. Construction of multifunctional linear polyphosphazene and molybdenum diselenide hybrids for efficient fire retardant and toughening epoxy resins
Zhou et al. Bifunctional linear polyphosphazene decorated by allyl groups: Synthesis and application as efficient flame-retardant and toughening agent of bismaleimide
CN113773513B (en) Graphite alkyne-hyaluronic acid composite flame retardant and preparation method and application thereof
Wang et al. Double-layered co-microencapsulated ammonium polyphosphate and mesoporous MCM-41 in intumescent flame-retardant natural rubber composites
Bao et al. Functionalized halloysite nanotubes endowing epoxy resin with simultaneously enhanced flame retardancy and mechanical properties
Feng et al. Ionic liquid modified boron nitride nanosheets for interface engineering of epoxy resin nanocomposites: Improving thermal stability, flame retardancy, and smoke suppression
Qiu et al. Phthalocyanine zirconium diazo passivation of black phosphorus for efficient smoke suppression, flame retardant and mechanical enhancement
Li et al. Enhancing the flame retardancy and UV resistance of polyamide 6 by introducing ternary supramolecular aggregates
Bao et al. The effect of strawberry-like nickel-decorated flame retardant for enhancing the fire safety and smoke suppression of epoxy resin
CN111320872B (en) Red phosphorus/polyimide covalent organic framework composite material with excellent flame retardant property and preparation method thereof
CN112321895A (en) Nano-silica-modified macromolecular flame-retardant char-forming agent and preparation method thereof
Ye et al. Engineering two nitrogen-containing polyhedral oligomeric silsesquioxanes (N-POSSs) to enhance the fire safety of epoxy resin endowed with superior thermal stability
Yu et al. Flame-retardant poly (L-lactic acid) with enhanced UV protection and well-preserved mechanical properties by a furan-containing polyphosphoramide
Li et al. Constructing cross-functional intumescent flame retardants with UV resistance for polypropylene composites

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant