CN110229412B

CN110229412B - PP (polypropylene) nano composite material and preparation method thereof

Info

Publication number: CN110229412B
Application number: CN201810183009.9A
Authority: CN
Inventors: 马永梅; 郑鲲; 张京楠; 曹新宇; 叶钢; 尚欣欣
Original assignee: Institute of Chemistry CAS
Current assignee: Institute of Chemistry CAS
Priority date: 2018-03-06
Filing date: 2018-03-06
Publication date: 2021-09-07
Anticipated expiration: 2038-03-06
Also published as: CN110229412A

Abstract

The invention relates to the field of nano composite materials, in particular to a PP nano composite material and a preparation method thereof, wherein the nano composite material is prepared by melting and blending a premix which is formed by filling and adhering a nano material combined with a liquid medium among polypropylene particles; the toughness of the nanocomposite material is improved along with the improvement of the strength and/or rigidity when the strength and/or rigidity is within a certain range. The preparation method comprises the steps of mixing a liquid medium and the nano material to obtain a paste, adhering the paste to the surface of the polypropylene particles, and carrying out melt blending to obtain the nano composite material. The nano composite material provided by the invention has the advantages of excellent toughness, short process flow and low cost, and is suitable for popularization and use.

Description

PP (polypropylene) nano composite material and preparation method thereof

Technical Field

The invention relates to the field of nano composite materials, in particular to a PP nano composite material and a preparation method thereof.

Background

In the prior art, a nano material and a polymer are often mixed and extruded to form a composite material, and although the tensile strength of the composite material is improved, the impact resistance of the composite material is generally low due to the problems of poor compatibility of the nano material and the polymer and the like.

In order to solve the above problems, intercalation in-situ polymerization and other methods are often adopted to enable the polymer to react among the gaps of the nano material so as to improve the impact resistance of the composite material, but the process takes a long time, the polymerization reaction conditions are harsh, the solvent is not easy to recover, and environmental pollution and other derivative problems are caused.

Patent No. CN101081928A proposes a method for preparing polyamide/nano montmorillonite master batch, which adopts water-assisted method to prepare polyamide/nano montmorillonite master batch, and the preparation method comprises using deionized water as intercalation agent, mixing purified montmorillonite and deionized water, fully dispersing to obtain montmorillonite slurry, gradually adding the slurry into polyamide whose formula amount is completely melted, and then extruding and granulating to obtain polyamide/nano montmorillonite master batch. The preparation method is simple, the production cost is low, but the montmorillonite slurry is added after the polyamide is melted, the montmorillonite slurry cannot be mixed with the copolymer completely, the polyamide cannot enter the interlayer in time due to the fact that interlayer water is gasified at high temperature, meanwhile, the energy generated by water gasification is not enough to strip the montmorillonite layers completely, and the product performance of the composite material cannot be completely stripped.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a nano composite material, which comprises a nano material and polypropylene, wherein gaps of the nano material are subjected to expansion treatment, intercalation in-situ polymerization is not required, and the toughness of the polypropylene nano composite material can be further improved while the strength is improved.

In order to achieve the purpose, the invention specifically adopts the following technical scheme:

a PP nanocomposite, wherein the nanocomposite is prepared by melt-blending a premix formed by filling and adhering a nanomaterial combined with a liquid medium between polypropylene particles; the toughness of the nanocomposite increases with increasing strength and/or stiffness.

In the scheme, the nano composite material taking the macromolecule as the base material has loss in toughness in the process of improving the mechanical property representing the strength, and sometimes even is lower than the toughness of the base material, so that the application range of the material is reduced; the reason for this is that some nano-material components in the composite material have poor compatibility with some polymers, and in addition, the nano-material itself generates agglomeration during the processing process and cannot be uniformly dispersed in the composite material, thereby causing some mechanical property deficiencies. The nano composite material provided by the invention is prepared by combining a liquid medium in a nano material, adhering and wrapping the nano material combined with the liquid medium on the surface of polypropylene particles to form a mixture, melting and blending the mixture, and enabling the liquid medium to generate phase change by utilizing a processing and heating process, so that the nano material is uniformly dispersed in polypropylene, and the toughness of the composite material is greatly improved.

In the above embodiment, the liquid medium at least includes water, and may further include isopentane, n-pentane, petroleum ether, hexane, cyclohexane, isooctane, trifluoroacetic acid, trimethylpentane, cyclopentane, heptane, butyl chloride, trichloroethylene, carbon tetrachloride, trichlorotrifluoroethane, propyl ether, toluene, p-xylene, chlorobenzene, o-dichlorobenzene, diethyl ether, benzene, isobutanol, ethylene dichloride, n-butanol, butyl acetate, propanol, methyl isobutyl ketone, tetrahydrofuran, ethyl acetate, isopropanol, ethanol, chloroform, methyl ethyl ketone, dioxane, pyridine, acetone, nitromethane, acetic acid, acetonitrile, dimethylformamide, methanol, methylamine, dimethylamine, diethyl ether, pentane, dichloromethane, carbon disulfide, 1, 1-dichloroethane, trifluoroacetic acid, 1,1, 1-trichloroethane, ethanol, butanone, ethyl chloride, toluene, p-xylene, chlorobenzene, o-dichlorobenzene, diethyl ether, ethyl chloride, n-butyl chloride, ethyl acetate, toluene, carbon disulfide, toluene, carbon disulfide, toluene, acetone, ethyl acetate, ethyl chloride, ethyl acetate, ethyl chloride, 1-ethyl chloride, 1, 1-ethyl chloride, 1-ethyl acetate, 1, 1-ethyl acetate, ethyl, 1, 2-dichloroethane, ethylene glycol dimethyl ether, triethylamine, propionitrile, 4-methyl-2-pentanone, ethylenediamine, butanol, acetic acid, ethylene glycol monomethyl ether, octane, morpholine, ethylene glycol monoethyl ether, xylene, m-xylene, acetic anhydride, o-xylene, N-dimethylformamide, cyclohexanone, cyclohexanol, furfural and N-methylformamide; preferably water.

The further scheme of the invention is as follows: the nano material comprises one or more of zero-dimensional nano material or one-dimensional nano material, and the liquid medium is injected into and fills the gaps of the nano material to form a paste with self-adhesion.

The further scheme of the invention is as follows: the thickness of the paste is 0-100 mm, but not 0 mm; the paste comprises: 1 part by weight of nano material and 0.02-100 parts by weight of liquid medium; preferably, the paste further comprises 0-50 parts by weight of an auxiliary agent, but not 0.

In the scheme, compared with the process of modifying, filtering and drying the nano material in the prior art, the nano material forms a continuous paste with certain self-adhesiveness after the liquid medium is injected into the gaps, the paste has certain consistency but not 0mm, and represents that the paste is a semisolid combined with the liquid medium and having certain fluidity, so that the nano material paste combined with the liquid medium can be uniformly adhered to the surface of polypropylene particles and is fed to a melting and blending device together with the polypropylene particles, and the processability is improved. Preferably, in order to increase the amount of the liquid medium to which the nanomaterial is bound, an auxiliary agent may be further added.

The further scheme of the invention is as follows: the zero-dimensional nano material and the one-dimensional nano material comprise one or more of nano silicon oxide, nano titanium oxide, nano zirconium oxide, nano zinc oxide, nano aluminum oxide, nano nickel oxide, nano gold, nano silver, nano silicon, nano carbon, carbon nano fiber, carbon nano tube, nano graphite, nano boron powder, nano sulfur, nano lanthanum oxide, nano neodymium oxide, nano erbium oxide, nano cerium oxide, nano praseodymium oxide, nano yttrium oxide, nano europium oxide, nano tungsten oxide, nano silicon carbide, nano tellurium oxide, nano niobium oxide, nano hafnium oxide or nano molybdenum oxide.

In the scheme, the ion exchange amount between the nano material and the liquid medium is low, and almost no ion exchange occurs, so that the liquid medium enters the nano material to form a paste with high viscosity and high liquid content, and further processing is facilitated.

The further scheme of the invention is as follows: the characterization parameters of the strength of the nano composite material comprise tensile strength, the characterization parameters of the rigidity comprise bending strength, the characterization parameters of the toughness comprise impact strength, and when the tensile strength of the nano composite material is within the range of 10-40 MPa and/or the bending strength is within the range of 15-55 MPa, the impact strength is improved by 10-80% along with the improvement of the tensile strength and/or the bending strength.

The further scheme of the invention is as follows: the mass ratio of the nano material to the polypropylene is 0.1-20: 100, preferably 1-10: 100, and more preferably 3-8: 100; the isotactic index of the polypropylene is 90-99.5%, and preferably 95-99%; the melt flow rate of the polypropylene is 0.1-2000 g/10min, preferably 0.2-100 g/10min, and more preferably 0.3-80 g/10 min.

In the scheme, because the isotactic index of the commonly adopted polypropylene is higher than 95% generally, the corresponding crystallinity is higher, the plasticizing temperature and the heat resistance are improved, but the toughness is reduced, and the polypropylene is filled into the nano material layer subjected to interlayer expansion treatment, so that the performance of the composite material in the toughness is improved greatly.

The invention also provides a preparation method of the polypropylene nano composite material, which is characterized by comprising the following steps:

(1) mixing and stirring the liquid medium and the nano material to obtain paste;

(2) mixing the paste obtained in the step (1) with polypropylene particles, and enabling the paste to be fully adhered among the polypropylene particles to obtain a premix;

(3) carrying out melt blending on the premix in the step (2) to obtain a nano composite material;

preferably, the step (1) further comprises mixing and stirring the liquid medium, the nano material and the auxiliary agent to obtain the paste.

In the method, because the liquid medium and the nano material are mixed to obtain the semisolid paste with a certain consistency, the paste and the polypropylene particles are mixed and then added into an extrusion device without slipping, the nano composite material can be prepared by direct feeding, the production and the processing are convenient, and the problem of poor performance of the nano composite material caused by premature gasification of the liquid medium in the prior art is solved.

According to the preparation method, in the step (3), during melt blending, when the temperature is higher than or equal to the plasticizing temperature of the thermoplastic polymer, the liquid medium in the nano mixed material is gasified, the gasification separates the agglomerated nano material, and simultaneously the gasification uniformly transfers heat in the thermoplastic polymer and the nano material; preferably, the gasification softens the thermoplastic polymer and lowers the plasticizing temperature of the thermoplastic polymer.

According to the preparation method, in the step (3), in the process that the temperature of melt blending is higher than the boiling point of the liquid medium and reaches the plasticizing temperature of polypropylene, the liquid medium is gasified, and the agglomerated nano material is separated; the boiling point of the liquid medium is lower than the plasticizing temperature of the polypropylene, the boiling point is preferably not higher than 180 ℃, and the liquid medium is preferably water; the weight ratio of the liquid medium to the nano material is 0.02-100: 1, preferably 5-50: 1, and more preferably 5-20: 1.

In the method, the nano material with high combined liquid medium content and the polypropylene are added into the processing equipment at the same time, and the liquid content of the nano material is improved due to the previous treatment (namely forming paste) on the lyophilic medium of the nano material, so that when the nano material enters a polypropylene melting zone, although the system temperature is higher than the boiling point of the liquid medium, the liquid medium contained in gaps of the nano material is more, so that the phase-change evaporation process and the melting process of the polypropylene can be carried out at the same time, the molten polypropylene can smoothly enter the gaps of the nano material, and the impact property of a final product is improved. In the prior art, the technical scheme of firstly melting the polymer and then adding the liquid-containing nano material is usually adopted, and due to insufficient treatment on the nano material lyophilic medium, the liquid medium is evaporated too fast, the compatibility of the nano material and polypropylene is reduced, and the toughness of the final product is reduced; on the other hand, in the prior art, the addition of the nano material after the polymer is melted undoubtedly prolongs the time for preparing the product, and wastes the time cost.

According to the preparation method, in the step (3), the premix obtained by mixing the paste and the polypropylene particles is fed to a hot melting processing device under the non-pressure condition for melt blending.

In the above method, the hot melt processing equipment includes, but is not limited to, an internal mixer, an open mill, or a screw extruder (parallel/conical/single/double/triple screw), and when the screw extruder is used, the premix obtained by mixing the dough with the polypropylene particles is fed from a non-pressure feeding zone to achieve feeding under a non-pressure condition. According to the invention, the nano material can be directly mixed with the polypropylene particles for feeding, and the nano material and the liquid medium are combined to form a paste with a certain consistency, so that the slipping phenomenon is prevented.

According to the preparation method, the step (1) further comprises the step of adding an auxiliary agent into the nano material to improve the liquid content of the nano material, so that the liquid medium combined with the nano material accounts for 50-98%, preferably 60-98% and more preferably 80-98% of the total mass of the paste; the mass ratio of the auxiliary agent to the nano material is 0.01-50: 1, preferably 0.1-5: 1, more preferably 0.2-1: 1, and the auxiliary agent comprises one or more of a carboxylate surfactant, a sulfate surfactant, a sulfonate surfactant, a phosphate surfactant, an amine salt surfactant, a quaternary ammonium salt surfactant, a heterocyclic surfactant, a nonionic surfactant, a natural water-soluble polymer, a synthetic water-soluble polymer and a prepolymer thereof.

In the method, the premix in the invention takes polypropylene as a base material and adopts a lower content of auxiliary agent in the preparation process, and the aim is to form an environment of lyophilic medium in the gaps of the nano material so as to improve the liquid content of the paste; compared with the high-content intercalation agent used in the intercalation polymerization in the prior art, the method greatly reduces the influence of the auxiliary agent on the overall performance of the nano composite material.

In the scheme, the addition of the auxiliary agent can improve the capability of a liquid medium entering the nano material, so that the consistency of the nano material mixture is increased; in addition, the addition of the auxiliary agent can also increase the boiling point of the liquid medium and prevent the liquid medium from gasifying and escaping in advance. The reaction temperature for generating the gel-like nano material in the invention can be at room temperature, and the requirement on the auxiliary agent is not high, so that the auxiliary agent applicable to the invention has wider alternative range.

The auxiliary agent includes but is not limited to one or more of the following components:

A. surfactant (b):

1. anionic surfactant: classified into carboxylates, sulfate ester salts, sulfonates, and phosphate ester salts.

(1) The soap is higher fatty acid salt, and the molecular structure general formula is (RCOO) -nMn +. Stearic acid, oleic acid, lauric acid and the like are commonly used. Depending on the metal ion (Mn +) thereof, there are alkali metal soaps, alkaline earth metal soaps, organic amine soaps and the like.

(2) The sulfated product is mainly sulfated oil and sulfate of higher fatty alcohol, and has molecular structure formula of ROSO3-M +, and commonly used sodium dodecyl sulfate (also known as "sodium lauryl sulfate"), sodium hexadecyl sulfate (also known as "sodium cetyl sulfate"), and sodium octadecyl sulfate (also known as "sodium stearyl sulfate").

(3) The sulfonic acid compound is mainly aliphatic sulfonic acid compound, sulfoaryl sulfonic acid compound, sulfonaphthalene sulfonic acid compound, etc

2. Cationic surfactant: the hydrophilic ions of the cationic surfactant contain nitrogen atoms, and are classified into amine salts, quaternary ammonium salts and heterocyclic rings according to the positions of the nitrogen atoms in the molecule. Such as benzalkonium chloride (trade name "benzalkonium chloride"), benzalkonium bromide (trade name "benzalkonium bromide"), cetylpyridinium chloride (bromide) (trade name "cetylpyridinium chloride"), etc

3. Zwitterionic surfactant: lecithin, amino acid type, betaine type

4. Nonionic surfactant: fatty glyceride, sorbitan fatty acid, polysorbate, alkylphenol polyoxyethylene, fatty alcohol polyoxyethylene, fatty acid methyl ester polyoxyethylene, and detergent.

B. The water-soluble polymer includes:

1. natural polymer

Starches

Marine algae species: sodium alginate and agar.

Vegetable gums: gum arabic, gum tragacanth, locust bean gum, tamarind seed polysaccharide gum, sesbania gum, carrageenan, guar gum, pectin.

Animal glue: gelatin, casein and chitosan.

Microbial glue: xanthan gum, gellan gum, hyaluronic acid.

2. Synthetic polymer and prepolymer thereof

(1) Water-soluble polymer and prepolymer thereof

Polyacrylamide, polyacrylic acid, polymethacrylic acid and copolymers thereof, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, polymaleic anhydride, polydimethyldiallyl ammonium chloride, polyvinylamine, polydivinyl imidazoline, sodium polystyrene sulfonate, sulfonated styrene maleic anhydride copolymer and Kelvin resin.

(2) Condensed water-soluble polymer and prepolymer thereof

The water-soluble epoxy resin is prepared from water-soluble amino resin, water-soluble phenolic resin, water-soluble alkyd resin, water-soluble epoxy resin, water-soluble polyurethane resin, polyethyleneimine, polyaspartic acid, polyepoxysuccinic acid, polyamide epichlorohydrin resin, polyamide glyoxal resin, ammonia-epichlorohydrin resin, heavy polyamine epichlorohydrin resin, ammonia-dimethylamine-epichlorohydrin resin, N-dimethyl-1, 3-propane diamine and epichlorohydrin resin.

(3) Others

Water-soluble maleic anhydride oil, dicyandiamide-formaldehyde resin, rosin amine-ethylene oxide polycondensate, poly N-vinyl acetamide and water-soluble polysucrose.

3. Semi-synthetic polymer

Modified cellulose and modified starch.

Synthetic polymers and prepolymers thereof are preferred.

According to the preparation method, the adding modes of the nano material and the auxiliary agent in the step (1) comprise one-time adding and batch adding; the addition rate is 0.01-100g/min, preferably 5-10g/min, more preferably 7 g/min.

According to the preparation method, the step (1) further comprises the step of carrying out physical dispersion on the nano material, wherein the physical dispersion comprises but is not limited to colloid milling, ball milling, ultrasound, vortex, etching assistance, airflow impact and the like; preferably, the physical dispersion is ultrasonic, the frequency of the ultrasonic field is 800-1000 Hz, and the power is 200-1000W.

According to the preparation method, the latex is added into the paste prepared in the step (1) to form a mixture, then the mixture and polypropylene are subjected to melt blending, the mass ratio of the latex to the paste is 0.1-10: 1, and the latex comprises one or more of styrene-acrylic emulsion, acrylate emulsion, acrylic emulsion, silicone-acrylic emulsion, waterborne polyurethane emulsion, fluorocarbon emulsion, rosin resin emulsion, terpineol, vinyl acetate-acrylic emulsion, waterborne epoxy resin emulsion, styrene-butadiene latex, natural latex, white latex, neoprene latex, pure acrylic latex, carboxylated styrene-butadiene latex and styrene-acrylic latex.

In the method, after the preparation of the nano material paste combined with the liquid medium is finished, the latex can be used for mixing the paste preform, and the paste subjected to the mixing treatment of the latex and the polypropylene are simultaneously melted and blended for subsequent processing, the mixing treatment greatly delays the release rate of the liquid medium in gaps, and effectively prevents the liquid medium from generating phase change prematurely.

According to the preparation method, the preparation method further comprises the step of adding an anti-aging agent into the premix formed by the paste and the polypropylene particles before or during melt blending, wherein the weight ratio of the anti-aging agent to the polypropylene is 0.1-1: 100, preferably 0.3: 100; the anti-aging agent is selected from one or more of amine antioxidant, phenol antioxidant, thiodipropionic acid vinegar antioxidant and phosphorous acid vinegar antioxidant.

In the above method, the anti-aging agent comprises:

amine antioxidant: ketone amine condensates, secondary diarylamines, substituted p-phenylenediamines, hindered amines;

phenol antioxidant: and can be classified into alkylated monophenols, alkylated polyphenols, thiobisphenols and polyphenols. The main varieties of alkylated monophenol and polyphenol antioxidants are antioxidants 264, 1076, 2246, 1035, 1010, 3114 and 1790; the main varieties of thiobisphenols are anti-aging agents 2246 and 300; the main varieties of the polyphenol antioxidant comprise 2, 5-di-tert-butyl hydrogen and 2, 5-di-tert-amyl hydroquinone;

thiodipropionic acid vinegar and phosphorous acid vinegar antioxidants; the main varieties of the antioxidant are antioxidant TNP, Ultranox624 and tris (2, 4-di-tert-butyl phenyl) phosphite.

Other types of antioxidants: 2-thiobenzimida is commercially available as antioxidant MB, nickel dibutyldithiocarbamate is commercially available as antioxidant NBC, and zinc dialkyldithiophosphate is also available.

The anti-aging agent specifically comprises: antioxidant RD, antioxidant AW, antioxidant BLE, antioxidant A, antioxidant OD, 4 '-bis (alpha-methylbenzyl) diphenylamine, 4' -bis (alpha, alpha-methylbenzyl) diphenylamine, N, -di-sec-butyl p-phenylenediamine, antioxidant 4030, antioxidant 4010NA, antioxidant 4020, antioxidant 264, antioxidant 1076, antioxidant 2216, antioxidant 1035, antioxidant 1010, antioxidant 3114, antioxidant 1790, antioxidant 2246, 2, 5-di-tert-butylhydroquinone, antioxidant DLTP, antioxidant TNP, Ultranox624, tris (2, 4-di-tert-butylphenyl) phosphite, antioxidant MB, antioxidant NBC and zinc dialkyldithiophosphate. .

The invention also provides a premix which comprises the paste and polypropylene; the paste comprises: 1 part of nano material, 5-100 parts of liquid medium and 0-50 parts of auxiliary agent by weight but not 0; the paste is adhered to the surface of the polypropylene particles to form a premix; preferably, in the process of preparing the paste, the nano material and the auxiliary agent are sequentially added into the liquid medium and dispersed; more preferably, the dispersing comprises ultrasound, shearing, stirring, ball milling, colloid milling, vortexing, etching assistance, or air flow impingement; further preferably, the addition modes of the nano material and the auxiliary agent comprise one-time addition and batch addition.

The preparation method of the polypropylene composite material specifically comprises the following steps:

(1) stirring the liquid medium, adding the nano material at the speed of 0.01-100g/min, and continuously stirring and dispersing uniformly, wherein the weight ratio of the liquid medium to the nano material is 0.02-100: 1;

(2) adding an auxiliary agent to the continuously stirred solution obtained in the step (1) in batches or at one time at a speed of 0.01-100g/min to obtain a paste, wherein the thickness of the paste is 0-100 mm, and the weight ratio of the auxiliary agent to the nano material is 0.001-50: 1;

(3) mixing the paste obtained in the step (2) with polypropylene particles to obtain a premix;

(4) and (4) feeding the premix obtained in the step (3) to a hot melting device under a non-pressure condition, melting and blending, and performing subsequent processing to obtain the nano composite material.

According to the method, when the hot melting equipment is a screw extruder, the rotating speed of a main machine is 30-80 Hz, the rotating speed of a main feeding hopper is 10-30 Hz, the extruding temperature is 150-200 ℃ in a first area, 230-280 ℃ in a second area, 230-280 ℃ in a third area, 230-280 ℃ in a fourth area and 230-280 ℃ in a fifth area; preferably, the rotating speed of the main machine is 60Hz, the rotating speed of the main feeding hopper is 20Hz, the extrusion temperature is 150-180 ℃ in the first zone, 245-260 ℃ in the second zone, 245-255 ℃ in the third zone, 240-250 ℃ in the fourth zone and 240-260 ℃ in the fifth zone. The linear speed of the screw rotating speed is 0.6-1 m/s.

The method also comprises the step of mixing the latex and the paste after the step (2) and then performing the process of the step (3).

The invention has the beneficial effects that:

1. the polypropylene nano composite material provided by the invention has the advantages of great improvement in mechanical properties, especially impact properties, simple process, easy operation, short time and suitability for popularization;

2. the invention melts the nano material with higher liquid content and the polypropylene at the same time, utilizes the heat in the processing process of the composite material to improve the molecular energy of the liquid medium combined between the gaps of the nano material, promotes the phase change of the liquid medium between the gaps, expands the gaps of the nano material, and is beneficial to the filling of the melted polypropylene into the gaps;

3. the nano material provided by the invention is processed by the aid to form a paste with higher liquid content, and in the process of simultaneous melting and processing with polypropylene, the time of phase change of a liquid medium combined among gaps is matched with the melting time of the polypropylene, so that the molten polypropylene can enter the gaps of the nano material to be filled;

4. the nano material provided by the invention plays a role in preventing the nano material from agglomerating while expanding the gap by utilizing the phase change of the liquid medium.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below, and the following embodiments are used for illustrating the present invention and are not used for limiting the scope of the present invention.

Example 1

In this example, the mass ratio of the nanomaterial to the polypropylene is 12:100, the liquid medium used is water, the auxiliary agent used is cetylpyridinium chloride, the nanomaterial used is nano alumina, and the nanocomposite is prepared by the following method:

(1) stirring the liquid medium, adding the nano material at the speed of 4.5g/min, continuously stirring and uniformly dispersing, wherein the weight ratio of the liquid medium to the nano material is 20: 1;

(2) adding an auxiliary agent to the continuously stirred solution obtained in the step (1) in batches or at one time at the speed of 0.1g/min to obtain a paste, wherein the thickness of the paste is 34mm, and the weight ratio of the auxiliary agent to the nano material is 10: 1;

(3) mixing the paste obtained in the step (2) with polypropylene to obtain a premix;

(4) and (4) melting, blending and carrying out subsequent processing on the premix obtained in the step (3) from a feed screw extruder in a non-pressure feeding area to obtain the nano composite material.

The rotating speed of a main machine of the extrusion equipment is 30Hz, the rotating speed of a main feeding hopper is 10Hz, the extrusion temperature is 150 ℃ in a first area, 230 ℃ in a second area, 240 ℃ in a third area, 280 ℃ in a fourth area, 260 ℃ in a fifth area, and the linear speed of the rotating speed of the screw is 0.8 m/s.

The polypropylene nanocomposite obtained by final extrusion granulation had a tensile strength of 29MPa, a flexural strength of 43MPa, and an impact strength of 81 kg. cm/cm.

Example 2

In this example, the mass ratio of the nanomaterial to the polypropylene is 10:100, the adopted liquid medium is acetone and water, the mass ratio of the acetone to the water is 7:93, the adopted auxiliary agent is polyacrylic acid and polymaleic anhydride, the weight ratio is 1:1, the adopted nanomaterial is nano silicon, and the nanocomposite is prepared according to the following method:

(1) stirring the liquid, adding the nano material at the speed of 10g/min, continuously stirring and uniformly dispersing, wherein the weight ratio of the liquid medium to the nano material is 100: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at the speed of 0.5g/min to obtain a paste, wherein the thickness of the paste is 25mm, and the weight ratio of the auxiliary agent to the nano material is 50: 1;

The rotating speed of a main machine of the extrusion equipment is 80Hz, the rotating speed of a main feeding hopper is 30Hz, the extrusion temperature in a first zone is 190 ℃, a second zone is 280 ℃, a third zone is 260 ℃, a fourth zone is 260 ℃ and a fifth zone is 250 ℃; the linear speed of the screw speed was 1 m/s.

The polypropylene nanocomposite obtained by final extrusion granulation had a tensile strength of 30MPa, a flexural strength of 41MPa, and an impact strength of 83 kg. cm/cm.

Example 3

In the embodiment, the mass ratio of the nano material to the polypropylene is 0.1:100, the adopted liquid medium is water, the adopted auxiliary agent is sodium alginate, the adopted nano material is nano zirconia and nano silicon carbide, and the mass ratio is 8:2, and the nano composite material is prepared according to the following method:

(1) stirring the liquid medium, adding the nano material at the speed of 0.01g/min, continuously stirring and uniformly dispersing, wherein the weight ratio of the liquid medium to the nano material is 50: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at the speed of 10g/min to obtain a paste, wherein the thickness of the paste is 38mm, and the weight ratio of the auxiliary agent to the nano material is 0.1: 1;

(4) and (4) melting, blending and performing subsequent processing on the premix internal mixer in the step (3) to obtain the nano composite material.

The tensile strength of the finally obtained polypropylene nano composite material is 28MPa, the bending strength is 40MPa, and the impact strength is 85 kg-cm/cm.

Example 4

In this embodiment, the mass ratio of the nanomaterial to the polypropylene is 7:100, the liquid medium is N, N-dimethylformamide, the auxiliary agent is polyethyleneimine or its oligomer, the nanomaterial is carbon nanotube, and the antioxidant is antioxidant BLE, and the nanocomposite is prepared by the following method:

(1) stirring a liquid medium, adding a nano material at a speed of 15g/min, continuously stirring and uniformly dispersing, and applying ultrasonic waves with the frequency of 800-1000 Hz and the power of 200-1000W, wherein the weight ratio of the liquid medium to the nano material is 5: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at the speed of 100g/min to obtain a paste, wherein the thickness of the paste is 59mm, and the weight ratio of the auxiliary agent to the nano material is 5: 1;

The rotating speed of a main machine of the extrusion equipment is 60Hz, the rotating speed of a main feeding hopper is 20Hz, the extrusion temperature of a first zone is 180 ℃, a second zone is 245 ℃, a third zone is 255 ℃, a fourth zone is 250 ℃ and a fifth zone is 240 ℃; the linear speed of the screw speed was 0.9 m/s.

The polypropylene nanocomposite obtained by final extrusion granulation had a tensile strength of 29MPa, a flexural strength of 42MPa, and an impact strength of 84 kg. cm/cm.

Example 5

In this example, the mass ratio of the nanomaterial to polypropylene is 4:100, the adopted liquid medium is cyclohexane and water, the mass ratio is 1:8, the adopted auxiliary agent is polyamide glyoxal resin, the adopted nanomaterial is carbon nanofiber, and the nanocomposite is prepared by the following method:

(1) stirring the liquid medium, adding the nano material at the speed of 20g/min, continuously stirring and uniformly dispersing, wherein the weight ratio of the liquid medium to the nano material is 0.8: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at the speed of 1g/min to obtain a paste, wherein the thickness of the paste is 49mm, and the weight ratio of the auxiliary agent to the nano material is 0.8: 1;

(4) and (4) feeding the premix obtained in the step (3) into an open mill, carrying out melt blending and subsequent processing to obtain the nano composite material.

The tensile strength of the finally obtained polypropylene nano composite material is 30MPa, the bending strength is 41MPa, and the impact strength is 86 kg-cm/cm.

Example 6

In this example, the mass ratio of the nanomaterial to the polypropylene is 4:100, the liquid medium used is water, the auxiliary agent used is tamarind seed polysaccharide gum, the nanomaterial used is nano niobium oxide, the anti-aging agent used is tris (2, 4-di-tert-butylphenyl) phosphite, and the nanocomposite is prepared according to the following method:

(1) stirring the liquid medium, adding the nano material at the speed of 0.02g/min, continuously stirring and uniformly dispersing, wherein the weight ratio of the liquid medium to the nano material is 10: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at the speed of 0.1g/min to obtain a paste, wherein the thickness of the paste is 39mm, the weight ratio of the auxiliary agent to the nano material is 2:1, and further, mixing the paste with pure acrylic latex;

(3) mixing the paste mixed with the pure acrylic latex obtained in the step (2) with polypropylene to obtain a premix;

The rotating speed of a main machine of the extrusion equipment is 60Hz, the rotating speed of a main feeding hopper is 30Hz, the extrusion temperature of a first zone is 160 ℃, a second zone is 245 ℃, a third zone is 280 ℃, a fourth zone is 260 ℃ and a fifth zone is 260 ℃; the linear speed of the screw speed was 0.7 m/s.

The polypropylene nanocomposite obtained by final extrusion granulation has a tensile strength of 37MPa, a bending strength of 50MPa, and an impact strength of 99 kg/cm.

Example 7

In this example, the mass ratio of the nanomaterial to polypropylene was 2:100, the liquid medium used was water and n-pentane, the mass ratio of water to n-pentane was 1:10, the adjuvant used was sodium dodecyl sulfate, the nanomaterial used was nano nickel oxide, and the nanocomposite was prepared according to the following method:

(1) stirring a liquid medium, adding the nano material at the speed of 20g/min, continuously stirring and uniformly dispersing, wherein the weight ratio of the liquid medium to the nano material is 40: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at the speed of 35g/min to obtain a paste, wherein the thickness of the paste is 81mm, and the weight ratio of the auxiliary agent to the nano material is 7: 1;

(4) and (4) melting and blending the premix obtained in the step (3) from a non-pressure feeding area feeding open mill, and performing subsequent processing to obtain the nano composite material.

The tensile strength of the finally obtained polypropylene nano composite material is 30MPa, the bending strength is 42MPa, and the impact strength is 86 kg-cm/cm.

Example 8

In this example, the mass ratio of the nanomaterial to the polypropylene is 4.5:100, the liquid medium used is water, the auxiliary agent used is hyaluronic acid, and the nanomaterial used is nano tellurium oxide, and the nanocomposite is prepared by the following method:

(1) stirring a liquid medium, adding a nano material at the speed of 0.5g/min, continuously stirring and uniformly dispersing, and applying ultrasonic waves with the frequency of 800-1000 Hz and the power of 200-1000W, wherein the weight ratio of the liquid medium to the nano material is 3.5: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at a speed of 56g/min to obtain a paste, wherein the thickness of the paste is 47mm, and the weight ratio of the auxiliary agent to the nano material is 28: 1;

The rotating speed of a main machine of the extrusion equipment is 70Hz, the rotating speed of a main feeding hopper is 20Hz, the extrusion temperature in a first zone is 200 ℃, a second zone is 230 ℃, a third zone is 280 ℃, a fourth zone is 230 ℃ and a fifth zone is 280 ℃; the linear speed of the screw speed was 0.6 m/s.

The polypropylene nanocomposite obtained by final extrusion granulation had a tensile strength of 28MPa, a flexural strength of 41MPa, and an impact strength of 84 kg. cm/cm.

Example 9

In this embodiment, the mass ratio of the nano material to the polypropylene is 18:100, the adopted liquid medium is water, the adopted auxiliary agent is chitosan and ammonia-dimethylamine-epichlorohydrin resin, the mass ratio of the chitosan to the ammonia-dimethylamine-epichlorohydrin resin is 10:1, the adopted nano material is nano yttrium oxide, and the nano composite material is prepared according to the following method:

(1) stirring a liquid medium, adding a nano material at the speed of 8g/min, continuously stirring and uniformly dispersing, and applying ultrasonic waves with the frequency of 800-1000 Hz and the power of 200-1000W, wherein the weight ratio of the liquid medium to the nano material is 40: 1;

(2) adding an auxiliary agent into the continuously stirred solution obtained in the step (1) at a speed of 15g/min to obtain a paste, wherein the thickness of the paste is 84mm, the weight ratio of the auxiliary agent to the nano material is 9:1, and further, mixing the paste with the fluorocarbon emulsion;

(3) mixing the paste mixed with the fluorocarbon emulsion obtained in the step (2) with polypropylene to obtain a premix;

The rotating speed of a main machine of the extrusion equipment is 70Hz, the rotating speed of a main feeding hopper is 30Hz, the first extrusion temperature is 155 ℃, the second extrusion temperature is 275 ℃, the third extrusion temperature is 270 ℃, the fourth extrusion temperature is 260 ℃, and the fifth extrusion temperature is 230 ℃; the linear speed of the screw speed was 1 m/s.

The polypropylene nanocomposite obtained by final extrusion granulation had a tensile strength of 36MPa, a flexural strength of 51MPa, and an impact strength of 103 kg. cm/cm.

Comparative example 1

In this comparative example, on the basis of example 1, the position where the liquid-containing nanomaterial was fed to the extruder was adjusted, polypropylene was fed under a non-pressure condition, and after the polypropylene passed through the melting zone, the nanomaterial feed containing the liquid medium in the voids was mixed with the molten polypropylene under pressure.

Comparative example 1 differs from the examples in that: the polypropylene and the nano material containing the liquid medium in the gaps are not simultaneously fed, but the polypropylene is fed firstly, and after the polypropylene is melted, the nano material with the liquid medium combined in the gaps is pressurized and fed for processing.

The polypropylene nanocomposite obtained by final extrusion granulation had a tensile strength of 24MPa, a flexural strength of 31MPa, and an impact strength of 52 kg. cm/cm.

Mechanical property tests were performed on examples 1 to 9 and comparative example 1, and the performance parameters of tensile strength, flexural strength and impact strength were respectively obtained as shown in the following table:

as can be seen from the above table, the mechanical properties of the nanocomposite obtained in examples 1 to 9 are all higher than those of comparative example 1, and especially the bending strength is greatly improved, but the present invention utilizes the phase change of the liquid medium to perform the expansion treatment on the nanomaterial, so that the polypropylene melted simultaneously with the nanomaterial enters the gaps to fill the gaps, the gap expansion treatment utilizes the heat generated by the polymer melting process to evaporate the liquid medium to generate implosion and prop open the gaps, and simultaneously utilizes the shear force of the extrusion process to further peel the gaps to fill the melted polypropylene, thereby improving the bending strength and impact strength of the product.

Further, the strength of the embodiment 6 and the embodiment 9 is higher than that of the embodiment 1 to 8, and the reason is that the nano material paste is subjected to latex mixing treatment before melting processing, so that the implosion force generated by evaporation of a liquid medium in the melting process is stronger, the expansion effect of the nano material gap is better, the polypropylene is filled more fully, and the mechanical strength of the final product is improved.

The foregoing is considered as illustrative of the preferred embodiments of the invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A PP nano composite material is characterized in that,

the nano composite material is prepared by melt blending of a premix formed by filling and adhering a nano material combined with a liquid medium among polypropylene particles; the nano material comprises one or more of zero-dimensional nano material or one-dimensional nano material, and the liquid medium is injected into and fills the gap of the nano material to form a paste with self-adhesion; the thickness of the paste is 0-100 mm, but not 0 mm;

the toughness of the nanocomposite material is improved along with the improvement of the strength and/or the rigidity;

the nano composite material is prepared by the following method:

(1) mixing and stirring a liquid medium, a nano material and an auxiliary agent to obtain a paste, and adding latex into the paste, wherein the mass ratio of the latex to the paste is 0.1-10: 1;

(2) mixing the mixture of the paste and the latex obtained in the step (1) with polypropylene particles, and enabling the paste to be fully adhered to the polypropylene particles to obtain a premix;

the liquid medium is water, and the mass ratio of the liquid medium to the nano material is 5-50: 1;

the step (1) also comprises the step of adding an auxiliary agent into the nano material to improve the liquid content of the nano material, so that the liquid medium combined with the nano material accounts for 50-98% of the total mass of the paste; the mass ratio of the auxiliary agent to the nano material is 0.01-50: 1;

in the step (3), the mixed materials are added into a solid conveying area of a double-screw extruder to be subjected to melt blending, wherein the extrusion temperature is 150-200 ℃ in a first area, 230-280 ℃ in a second area, 230-280 ℃ in a third area, 230-280 ℃ in a fourth area and 230-280 ℃ in a fifth area, and the nano composite material is obtained.

2. The PP nanocomposite of claim 1, wherein the zero-dimensional nanomaterials and one-dimensional nanomaterials comprise one or more of nano-silica, nano-titania, nano-zirconia, nano-zinc oxide, nano-alumina, nano-nickel oxide, nano-gold, nano-silver, nano-silica, nano-carbon, carbon nanofibers, carbon nanotubes, nano-graphite, nano-boron powder, nano-sulfur, nano-lanthanum oxide, nano-neodymium oxide, nano-erbium oxide, nano-cerium oxide, nano-praseodymium oxide, nano-yttrium oxide, nano-europium oxide, nano-tungsten oxide, nano-silicon carbide, nano-tellurium oxide, nano-niobium oxide, nano-hafnium oxide, or nano-molybdenum oxide.

3. The PP nanocomposite according to claim 1, wherein the nanocomposite strength characteristic parameter comprises tensile strength, the stiffness characteristic parameter comprises flexural strength, the toughness characteristic parameter comprises impact strength, the nanocomposite has a tensile strength in the range of 10 to 40MPa, and/or the flexural strength in the range of 15 to 55MPa, the impact strength increases by 10 to 80% with increasing tensile and/or flexural strength.

4. The PP nanocomposite material according to any one of claims 1 to 3, wherein the mass ratio of the nanomaterial to the polypropylene is 0.1 to 20: 100; the isotactic index of the polypropylene is 90-99.5%; the melt flow rate of the polypropylene is 0.1-2000 g/10 min.

5. The composite material according to claim 4, wherein the mass ratio of the nano material to the polypropylene is 1-10: 100; the isotactic index of the polypropylene is 95-99%; the melt flow rate of the polypropylene is 0.2-100 g/10 min.

6. The composite material according to claim 5, wherein the mass ratio of the nano material to the polypropylene is 3-8: 100; the melt flow rate of the polypropylene is 0.3-80 g/10 min.

7. A method for preparing the polypropylene nanocomposite as claimed in any one of claims 1 to 6, comprising the steps of:

8. The preparation method according to claim 7, wherein in the step (3), during the process that the temperature of the melt blending is higher than the boiling point of the liquid medium and the plasticizing temperature of the polypropylene is reached, the liquid medium is gasified, and the agglomerated nanometer materials are separated.

9. The preparation method according to claim 7, wherein the weight ratio of the liquid medium to the nanomaterial is 5-20: 1.

10. The method according to claim 7, wherein the auxiliary agent comprises one or more of a carboxylate surfactant, a sulfate surfactant, a sulfonate surfactant, a phosphate surfactant, an amine salt surfactant, a quaternary ammonium salt surfactant, a heterocyclic surfactant, a nonionic surfactant, a natural water-soluble polymer, a synthetic water-soluble polymer, and a prepolymer thereof.

11. The preparation method according to claim 7, wherein the step (1) further comprises adding an auxiliary agent into the nano material to increase the liquid content of the nano material, so that the liquid medium combined with the nano material accounts for 60-98% of the total mass of the paste; the mass ratio of the auxiliary agent to the nano material is 0.1-5: 1.

12. The preparation method according to claim 11, wherein the step (1) further comprises adding an auxiliary agent into the nano material to increase the liquid content of the nano material, so that the liquid medium combined with the nano material accounts for 80-98% of the total mass of the paste; the mass ratio of the auxiliary agent to the nano material is 0.2-1: 1.

13. The preparation method of claim 7, wherein the latex comprises one or more of styrene-acrylic emulsion, acrylate emulsion, acrylic emulsion, silicone-acrylic emulsion, aqueous polyurethane emulsion, fluorocarbon emulsion, rosin resin emulsion, terpineol, vinyl acetate-acrylic emulsion, aqueous epoxy resin emulsion, styrene-butadiene latex, natural latex, white latex, neoprene latex, pure acrylic latex, carboxylic styrene-butadiene latex and styrene-acrylic latex.