CN113024822B - High-activity low-residue degradable chain extender and preparation method thereof - Google Patents
High-activity low-residue degradable chain extender and preparation method thereof Download PDFInfo
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- CN113024822B CN113024822B CN202110406394.0A CN202110406394A CN113024822B CN 113024822 B CN113024822 B CN 113024822B CN 202110406394 A CN202110406394 A CN 202110406394A CN 113024822 B CN113024822 B CN 113024822B
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- chain extender
- glycidyl methacrylate
- degradable
- degradable resin
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- 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
- C08G81/00—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers
- C08G81/02—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers at least one of the polymers being obtained by reactions involving only carbon-to-carbon unsaturated bonds
- C08G81/024—Block or graft polymers containing sequences of polymers of C08C or C08F and of polymers of C08G
- C08G81/027—Block or graft polymers containing sequences of polymers of C08C or C08F and of polymers of C08G containing polyester or polycarbonate sequences
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
- Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics
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- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polyesters Or Polycarbonates (AREA)
- Epoxy Resins (AREA)
- Other Resins Obtained By Reactions Not Involving Carbon-To-Carbon Unsaturated Bonds (AREA)
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Abstract
The invention discloses a high-activity, low-residue and degradable chain extender and a preparation method thereof; the paint comprises the following components: 60-80 parts of degradable resin; 40-20 parts of glycidyl methacrylate copolymer. The preparation of the chain extender comprises the following steps: the raw materials are uniformly mixed by a mixer, then fed into a double-screw extruder, subjected to melt grafting reaction under the conditions that the temperature is adjusted to be 140-220 ℃ and the screw rotating speed is 200-500 rpm, and extruded and granulated. Compared with the prior art, the degradable resin is used as the base material, so that the degradability of the chain extender is ensured; the chain extender has high epoxy content, and is added in a proper amount and easy to disperse uniformly when being added into degradable resin for modification. The preparation method of the invention has no monomer pollution, is simple and easy to implement and is easy for industrial production; can be widely used in the fields of secondary modification of degradable resin and the like, and has very wide application prospect and industrial value.
Description
Technical Field
The invention relates to the technical field of high polymer materials, in particular to a high-activity low-residue degradable chain extender and a preparation method thereof.
Background
Polylactic acid (PLA) is a non-toxic and non-irritating synthetic polymer material, and is prepared from lactic acid, mainly from fermentation of starch (such as corn and rice), or from cellulose, kitchen waste or fish waste. PLA raw materials are wide in source, and products prepared from the PLA raw materials can be directly composted after being used, so that CO2 and H2O can be completely reduced, and the requirements of sustainable development are met. PLA is mainly used in disposable articles such as disposable tableware and packaging materials.
Polylactic acid has poor toughness and high cost, and these disadvantages limit the practical application of PLA. In practical application, PLA is usually modified by filling with starch or made into alloy with other materials. When PLA is blended and modified with other materials, a chain extender needs to be added to improve the compatibility of filling modification or blending alloy modification. However, most of the chain extenders on the market are non-degradable compatibilizers. How to achieve both chain extension and degradation is a very contradictory problem.
The Chinese patent application with publication number CN102603994A discloses a glycidyl methacrylate grafted polylactic acid copolymer material, a preparation method and application thereof, and a free radical initiator is adopted to initiate glycidyl methacrylate grafted polylactic acid. But the grafting rate is only 1-5%, most of monomers can react with polylactic acid in the grafting process, the chain extension reaction activity is low, the monomers are heavily used in the later period, the addition amount is large, and the chain extension efficiency is low.
The publication number CN201811517424.X Chinese patent application discloses a polylactic acid chain extender, a preparation method thereof and modified polylactic acid, wherein a glycidyl acrylate monomer is adopted to irradiate and graft a polylactic acid polymer. A large amount of ester monomers are used in the paper, which causes environmental pollution, difficult charging and high monomer residue. And research common knowledge indicates that it is difficult to achieve a grafting ratio of more than 5% by the monomer grafting method.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a high-activity, low-residue and degradable chain extender and a preparation method thereof.
The purpose of the invention is realized by the following technical scheme:
the invention provides a chain extender, which comprises the following components in parts by weight based on 100 parts by weight:
60-80 parts of degradable resin;
40-20 parts of glycidyl methacrylate copolymer;
the chain extender is prepared by a method comprising the following steps:
and mixing the degradable resin and the glycidyl methacrylate copolymer, carrying out melting reaction and granulating to obtain the degradable chain extender.
In one embodiment of the present invention, the glycidyl methacrylate unit in the glycidyl methacrylate copolymer accounts for 15 to 60 wt% of the polymer. If the proportion is too low, the prepared chain extender has low activity and high downstream addition amount and cannot be used; if the proportion is too high, the chain extender has too high activity, the downstream addition amount is low, the use is inconvenient, and crosslinking is easily caused.
In one embodiment of the present invention, the weight average molecular weight Mw of the degradable resin is 10 to 30 ten thousand. If the molecular weight is too low, the concentration of the end group is too high, the molecules are easy to move, and the reaction activity is too strong; the molecular weight is too high, the end group concentration is too low, and the grafting reaction effect cannot be ensured.
As an embodiment of the invention, the concentration of the carboxyl end groups of the degradable resin is less than or equal to 40 mol/t. And the concentration of the end group is too high, epoxy groups are excessively consumed, crosslinking is easily caused, and the using effect of the chain extender is reduced.
As an embodiment of the present invention, the degradable resin is at least one of polylactic acid PLA, poly (butylene terephthalate-CO-butylene adipate) ester PBAT, polybutylene succinate PBS, and polybutylene succinate adipate PBSA.
As an embodiment of the present invention, the glycidyl methacrylate copolymer is a copolymer of one or more of styrene, ethylene, methyl methacrylate, methyl acrylate, acrylonitrile, butyl acrylate, and glycidyl methacrylate.
In one embodiment of the present invention, the melt reaction is carried out at a temperature of 140 to 220 ℃ and a screw rotation speed of 300 to 500 rpm.
According to one embodiment of the invention, the degradable resin and the glycidyl methacrylate copolymer are dry-mixed, uniformly mixed and then fed into a double-screw extruder for melt reaction; and granulating to obtain the degradable chain extender.
As an embodiment of the present invention, the twin-screw extruder is a reactive twin-screw extruder. As an embodiment of the present invention, the length to diameter ratio of the screws of the twin-screw extruder is 35 or more.
The method utilizes the residual carboxyl-terminated groups on the degradable resin to react with the epoxy polymer to perform extrusion grafting reaction, has no monomer residue, no initiator residue and no solvent residue, optimizes various process conditions, and controls the reaction rate.
Compared with the prior art, the invention has the following beneficial effects:
1) the invention adopts degradable resin as the base material, thus ensuring the degradability of the chain extender; the biological decomposition rate of the chain extender is more than or equal to 60% theoretically;
2) the glycidyl methacrylate copolymer adopted by the invention has high epoxy content, and the chain extender is added in a proper amount and is easy to disperse and uniform when being added into the degradable resin for modification;
3) the preparation method of the invention has no monomer pollution, is simple and easy to implement and is easy for industrial production; the product prepared by the method has high cost performance, can be widely used in the fields of secondary modification of degradable resin and the like, and has very wide application prospect and industrial value.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
The degradable resin used in the invention is polylactic resin (PLA number average molecular weight is 10 ten thousand, Natureworks4032D, carboxyl end group content is 25 mol/t). PBAT is BASF ecoflex C1200.
The glycidyl methacrylate copolymer used in the embodiment of the invention is free radical polymerization styrene-glycidyl methacrylate copolymer SG, (SG-15, SG-30 and SG-60 respectively correspond to the weight content of glycidyl methacrylate, and are respectively 15 wt%, 30 wt% and 60 wt%)
In the invention, the performance test of the obtained sample is carried out according to the following method:
1. titration of epoxy content:
weighing a certain amount of dry product, dissolving in chloroform, adding 0.5ml of 1.2mol/L hydrochloric acid solution to open epoxy group after the sample is completely dissolved, then titrating with 0.05mol/L potassium hydroxide ethanol solution until the color is red as an end point (the indicator is phenolphthalein ethanol solution), and calculating the epoxy content according to the following formula
Epoxy content ═ V (V)HCl·CHCl-VKOH·CKOH)MGMA】/Ws
In the formula VHCl、VKOHVolume (L) of hydrochloric acid and potassium hydroxide consumed, CHCl、CKOHIs the concentration (mol/L) of hydrochloric acid and potassium hydroxide, MGMA is the molecular weight of GMA and Ws is the sample weight.
2. Titration of carboxyl end group content
Tetrachloroethane is adopted: refluxing the phenol (1: 1) solution at 140 deg.C to dissolve the polymer, cooling to room temperature, titrating with 0.05mol/L potassium hydroxide ethanol solution until the blue color is the end point (indicator is bromophenol blue indicator), and calculating the carboxyl end group content according to the following formula
Content of terminal carboxyl group [ V-V ]0)c*103】/m
V-standard titration volume of KOH-ethanol consumed in the formula, ml, V0The volume of potassium hydroxide-ethanol standard titration solution consumed as a blank is ml; c-potassium hydroxide-ethanol standard titration solution concentration, mol/l; m-weight sample mass, g.
3. Mechanical Property test
Notched impact properties of the materials were tested using a cantilever beam impact instrument. The dimensions of the impact bars were length by width by thickness (80 by 10 by 4mm) and the depth of the indentations 2 mm. The impact energy was 5.5J. 5 bars were tested per group and the impact strength was averaged over 5 bars.
In order to make the technical problems and embodiments to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to examples.
Example 1
Weighing 60% of polylactic resin and 1540% of glycidyl methacrylate copolymer SG-based on weight percentage as a mixed material; adding the mixed material into a double-screw extruder, carrying out melt extrusion, and granulating to obtain a granular product (namely PLA-g-GMA copolymer material). In the scheme, a co-rotating twin-screw extruder is adopted, and the temperature is 140 ℃, 160 ℃, 180 ℃, 200 ℃, 220 ℃, 200 ℃ and 190 ℃. The length-diameter ratio of the twin screw is 35, and the screw rotating speed is 300 rpm. And carrying out melt grafting reaction. And granulating and post-treating to obtain the polylactic acid-based graft product. The epoxy content and carboxyl end group concentration of the sample are shown in Table 1.
Example 2
Weighing 70% of polylactic resin and 70% of glycidyl methacrylate copolymer SG-3030% as mixed materials according to the weight percentage; and adding the mixed material into a double-screw extruder for melt extrusion and granulation to obtain a granular product (namely PLA-g-GMA copolymer material). In the scheme, the temperature of a co-rotating double-screw extruder is 140 ℃, 160 ℃, 180 ℃, 200 ℃, 220 ℃, 200 ℃ and 180 ℃. The length-diameter ratio of the twin screw is 45, and the screw rotating speed is 400 rpm. And carrying out melt grafting reaction. And granulating and post-treating to obtain the polylactic acid-based graft product. The epoxy content and carboxyl end group concentration of the sample are shown in Table 1.
Example 3
Weighing 80% of polylactic resin and SG-6020% of glycidyl methacrylate copolymer as a mixed material according to the weight percentage; and adding the mixed material into a double-screw extruder for melt extrusion and granulation to obtain a granular product (namely PLA-g-GMA copolymer material). In the scheme, the temperature of a co-rotating double-screw extruder is 140 ℃, 150 ℃, 180 ℃, 200 ℃, 220 ℃, 200 ℃ and 180 ℃. The length-diameter ratio of the twin screw is 55, and the screw rotating speed is 500 rpm. And carrying out melt grafting reaction. And granulating and post-treating to obtain the polylactic acid-based graft product. The epoxy content and carboxyl end group concentration of the sample are shown in Table 1.
Comparative example 1
Weighing polylactic resin according to weight percentage; adding the polylactic acid into a double-screw extruder for melt extrusion and granulation to obtain a granular product. In the scheme, the temperature of a co-rotating double-screw extruder is 140 ℃, 160 ℃, 180 ℃, 200 ℃, 220 ℃, 200 ℃, 190 ℃. The length-diameter ratio of the twin screw is 35, and the screw rotating speed is 300 rpm. And carrying out melt grafting reaction. And granulating and post-treating to obtain a comparative product. The epoxy content and carboxyl end group concentration of the sample are shown in Table 1.
Comparative example 2
Weighing 97% of polylactic resin and SG-603% of glycidyl methacrylate copolymer as a mixed material according to the weight percentage; and adding the mixed material into a double-screw extruder for melt extrusion and granulation to obtain a granular product (namely PLA-g-GMA copolymer material). In the scheme, the temperature of a co-rotating double-screw extruder is 140 ℃, 150 ℃, 180 ℃, 200 ℃, 220 ℃, 200 ℃ and 180 ℃. The length-diameter ratio of the twin screw was 55 and the screw rotation speed was 500 rpm. And carrying out melt grafting reaction. And granulating and post-treating to obtain the polylactic acid-based graft product. The epoxy content and carboxyl end group concentration of the sample are shown in Table 1.
The evaluation and results of examples 1 to 3 and comparative examples 1 and 2 are shown in Table 1:
TABLE 1
Table 1 the results show that: comparative example 1 illustrates that the polylactic acid raw material is pelletized by a twin-screw extruder to be thick, and the end group concentration of the polylactic acid raw material is increased from 25mol/t to 33mol/t of the raw material, thereby reflecting the degradation behavior of the polylactic acid under the condition of being subjected to thermal shearing. Comparative example 2 also had some reduction in the terminal group content, but the epoxy content was very low, only 1.3 wt%. The end group contents of examples 1 to 3 were all reduced considerably. The grafting reaction of the polylactic acid raw material and the glycidyl methacrylate copolymer is shown. The epoxy contents of examples 1-3 were also somewhat reduced from the theoretical diluted values, indicating the occurrence of grafting reactions. At the same time, the epoxy contents of examples 1 to 3 were still high, indicating that the grafting yield of epoxy was high.
Application evaluation effect experiment: weighing polylactic resin, PBAT resin and a chain extender according to the weight percentage, and adding the weighed materials into a high-speed mixer to mix for 1 minute. Then adding the mixture into a double-screw extruder for melt extrusion and granulation. And tabletting by a tabletting machine, and cutting to obtain the sample strip.
TABLE 2
Table 2 results show that comparative example 1 was evaluated to have an impact strength of only 7KJ/m2PLA is poorly compatible with PBAT. Comparative example 2 was evaluated to add PLA-D2 and the impact strength was improved, but the effect was not significant, mainly due to too low reactivity.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (6)
1. The chain extender is characterized by comprising the following components in parts by weight based on 100 parts by weight:
60-80 parts of degradable resin;
40-20 parts of glycidyl methacrylate copolymer;
the glycidyl methacrylate unit in the glycidyl methacrylate copolymer accounts for 15-60 wt% of the polymer;
the weight average molecular weight Mw of the degradable resin is 10-30 ten thousand, and the carboxyl end group concentration is less than or equal to 40 mol/t; the degradable resin is at least one of polylactic acid (PLA), poly (butylene terephthalate-CO-butylene adipate) ester (PBAT), Poly Butylene Succinate (PBS) and poly butylene succinate-adipate (PBSA);
the chain extender is prepared by a method comprising the following steps:
and mixing the degradable resin and the glycidyl methacrylate copolymer, carrying out melt reaction, and granulating to obtain the degradable chain extender.
2. The chain extender of claim 1, wherein the glycidyl methacrylate copolymer is a copolymer of one or more of styrene, ethylene, methyl methacrylate, methyl acrylate, acrylonitrile, butyl acrylate and glycidyl methacrylate.
3. The chain extender of claim 1, wherein the melt reaction is carried out at a temperature of 140 to 220 ℃ and a screw rotation speed of 300 to 500 rpm.
4. The chain extender of claim 1, wherein the degradable resin and the glycidyl methacrylate copolymer are dry-mixed, uniformly mixed and then fed into a double-screw extruder for melt reaction; and granulating to obtain the degradable chain extender.
5. The chain extender of claim 4, wherein the twin screw extruder is a reactive twin screw extruder.
6. The chain extender of claim 4, wherein the length to diameter ratio of the screws of the twin screw extruder is 35 or more.
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| CN113881057B (en) * | 2021-11-11 | 2022-06-07 | 中国科学院长春应用化学研究所 | High molecular weight polylactic acid-based copolymer and preparation method thereof |
| CN114539568B (en) * | 2022-03-15 | 2024-03-22 | 福建长泰万泰矿物制品有限公司 | Biodegradable plastic, preparation method and application thereof |
| CN115960344A (en) * | 2022-12-22 | 2023-04-14 | 东营市鑫玉翔新材料科技有限公司 | Chain-extended block particle, and preparation and application thereof |
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| CN106916424A (en) * | 2017-04-07 | 2017-07-04 | 常州大学 | A kind of high-tenacity heat-resistant type full-biodegradable polylactic acid material and preparation method thereof |
| CN111499789A (en) * | 2020-04-17 | 2020-08-07 | 佳易容聚合物(上海)有限公司 | Solvent-free tackifying chain extender and preparation method and application thereof |
| CN112279985A (en) * | 2020-11-01 | 2021-01-29 | 福建师范大学 | Degradable chain extender and preparation method and application thereof |
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| CN106916424A (en) * | 2017-04-07 | 2017-07-04 | 常州大学 | A kind of high-tenacity heat-resistant type full-biodegradable polylactic acid material and preparation method thereof |
| CN111499789A (en) * | 2020-04-17 | 2020-08-07 | 佳易容聚合物(上海)有限公司 | Solvent-free tackifying chain extender and preparation method and application thereof |
| CN112552444A (en) * | 2020-04-17 | 2021-03-26 | 佳易容聚合物(上海)有限公司 | Preparation method of solvent-free tackifying chain extender |
| CN112279985A (en) * | 2020-11-01 | 2021-01-29 | 福建师范大学 | Degradable chain extender and preparation method and application thereof |
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