A composite material prepared based on dynamic vulcanization and a preparation method thereof
By using dynamic vulcanization technology and synergistic modification with attapulgite, composite materials were prepared to construct a cross-linked EVA microdomain/PLA matrix structure, which improved the toughness and strength of polylactic acid and solved the problems of high brittleness and poor toughness of PLA materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YANCHENG INST OF TECH
- Filing Date
- 2026-04-21
- Publication Date
- 2026-07-24
AI Technical Summary
Polylactic acid (PLA) materials are brittle and have poor toughness. There are no reports on the synergistic modification of EVA, attapulgite and PLA through dynamic vulcanization in the current technology.
The composite material was prepared using dynamic vulcanization technology. The composition included polylactic acid, ethylene-vinyl acetate copolymer, attapulgite, peroxide crosslinking agent, co-crosslinking agent, antioxidant and compatibilizer. The composite material was melt-blended using a twin-screw extruder and the premixed liquid was injected into the side feed port to carry out the crosslinking reaction, thereby constructing a 'crosslinked EVA microdomain/PLA matrix' structure.
It significantly improves the toughness and elongation at break of the material, and increases the tensile strength and notched impact strength, thus solving the problem of PLA's high brittleness and difficulty in achieving both strength and toughness.
Smart Images
Figure CN122445153A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to a composite material prepared by dynamic vulcanization and its preparation method. Background Technology
[0002] Polylactic acid (PLA) is a biodegradable polymer derived from renewable resources. It possesses good mechanical properties and processability, but its brittleness and poor toughness limit its applications. Ethylene-vinyl acetate copolymer (EVA) exhibits excellent flexibility and elasticity and is often used for toughening modification. Attapulgite (AT) is a natural nanofiber silicate mineral with high specific surface area, good adsorption, and reinforcing properties. Dynamic vulcanization technology can crosslink the rubber phase during melt blending, forming a "sea-island" structure that significantly improves the material's elasticity, strength, and durability.
[0003] There are currently no reports on the synergistic modification of EVA, attapulgite, and PLA through dynamic vulcanization. Summary of the Invention
[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.
[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.
[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a composite material based on dynamic vulcanization and its preparation method.
[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a composite material prepared based on dynamic vulcanization, wherein the composite material is composed of polylactic acid, ethylene-vinyl acetate copolymer, attapulgite, peroxide crosslinking agent, co-crosslinking agent, antioxidant and compatibilizer; The composition, by mass parts, is as follows: polylactic acid 80-95 parts; ethylene-vinyl acetate copolymer 5-20 parts; attapulgite 1-5 parts; peroxide crosslinking agent 0.2-2 parts; co-crosslinking agent 0.1-1 parts; antioxidant 0.1-0.5 parts; and compatibilizer 1-5 parts.
[0008] As a preferred embodiment of the composite material of the present invention, wherein, by weight parts, polylactic acid is 80-95 parts; ethylene-vinyl acetate copolymer is 10-15 parts; attapulgite is 2-5 parts; peroxide crosslinking agent is 0.5-1.5 parts; co-crosslinking agent is 0.2-0.8 parts; antioxidant is 0.2-0.4 parts; and compatibilizer is 2-4 parts.
[0009] As a preferred embodiment of the composite material of the present invention, the following components are included by mass: polylactic acid 85 parts; ethylene-vinyl acetate copolymer 15 parts; attapulgite 4 parts; peroxide crosslinking agent 0.8 parts; co-crosslinking agent 0.6 parts; antioxidant 1 part; and compatibilizer 4 parts.
[0010] As a preferred embodiment of the composite material of the present invention, the peroxide crosslinking agent includes one or more of dicumyl peroxide, benzoyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.
[0011] As a preferred embodiment of the composite material of the present invention, the crosslinking agent includes one or more of trimethylolpropane trimethacrylate, triallyl isocyanurate, and divinylbenzene.
[0012] As a preferred embodiment of the composite material of the present invention, the compatibilizer includes one or more of ethylene-acrylic acid copolymer and epoxy-functionalized styrene-vinyl acetate copolymer.
[0013] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a composite material based on dynamic vulcanization, comprising: weighing each component according to the stated mass fractions and vacuum drying PLA, EVA, and AT; adding PLA, EVA, AT, compatibilizer, and antioxidant to a twin-screw extruder; injecting a premix of peroxide crosslinking agent and co-crosslinking agent through a side feed port when the blending process has reached the 2nd to 4th minute; continuing the dynamic vulcanization reaction for 2 to 5 minutes to allow the EVA phase to crosslink in situ; extruding, water cooling, and pelletizing to obtain the thermoplastic composite material.
[0014] As a preferred embodiment of the preparation method described in this invention, the PLA is vacuum dried at 60-80℃ for 8-12 h, the EVA is dried at 50-70℃ for 6-8 h, and the AT is dried at 100-110℃ for 3-5 h.
[0015] In a preferred embodiment of the preparation method described in this invention, the melt blending temperature is 160–180°C.
[0016] As a preferred embodiment of the preparation method of the present invention, the premixed liquid is prepared by pre-dispersing a peroxide crosslinking agent and a co-crosslinking agent in epoxidized soybean oil to form a premixed liquid with a mass concentration of 30-60%.
[0017] Beneficial effects of this invention: This invention constructs a "crosslinked EVA microregion / PLA matrix" structure through dynamic vulcanization, which significantly improves the toughness and elongation at break of the material; it also introduces AT to enhance interfacial interactions, suppress phase separation, and improve tensile strength and elongation at break. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a scanning electron microscope image of Example 2. Detailed Implementation
[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.
[0020] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0021] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0022] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available. See Table 1 for details.
[0023] Table 1
[0024] Example 1 This embodiment provides a method for preparing a composite material based on dynamic vulcanization, specifically as follows: (1) Prepare raw materials: PLA 90 parts, EVA 10 parts, AT 4 parts, crosslinking agent dicumyl peroxide (DCP) 0.4 parts, co-crosslinking agent trimethylolpropane trimethacrylate (TMPTMA) 0.2 parts, compatibilizer EAA 2 parts, antioxidant 1010 0.2 parts, epoxidized soybean oil 2 parts.
[0025] (2) Preparation process: The crosslinking agent and the co-crosslinking agent were added to 2 parts of epoxidized soybean oil and mixed to prepare a premix. PLA was vacuum dried at 70℃ for 12 h, EVA was dried at 60℃ for 8 h, and AT was dried at 105℃ for 4 h. The components were weighed according to the above formula. PLA, EVA, EAA, AT and antioxidant 1010 were added to a twin-screw extruder and melt-blended at 170℃ and screw speed of 200 rpm. When the blending reached the 2nd minute, the premix was injected through the side feed port and the reaction continued for 3 minutes. The mixture was extruded, cooled and granulated to obtain a thermoplastic composite material.
[0026] The obtained material was tested according to GB / T 1040.1-2025 standard using a microcomputer-controlled electronic universal testing machine (CMT6503, Youhong Measurement & Control Technology (Shanghai) Co., Ltd.), and the tensile strength was 18.2 MPa, with an elongation at break of 180%. The notched impact strength was measured according to GB / T1843.2-2008 using a simply supported beam impact testing machine (XJJY-5, Chengde Kecheng Testing Machine Co., Ltd.), and was 15.3 KJ / m². 2 .
[0027] Example 2 The difference from Example 1 is that there are 85 parts of PLA and 15 parts of EVA, but the rest is the same as in Example 1.
[0028] like Figure 1 The image shown is an electron microscope image of the material prepared in this embodiment. The tensile strength of the obtained material is 16.5 MPa, the elongation at break is 264%, and the notched impact strength is 18.3 KJ / m. 2 .
[0029] Example 3 The difference from Example 1 is that there are 80 parts of PLA and 20 parts of EVA, but the rest is the same as in Example 1.
[0030] The resulting material has a tensile strength of 15.5 MPa, an elongation at break of 315%, and a notched impact strength of 22.7 KJ / m. 2 .
[0031] Performance tests were conducted on Examples 1-3, and the test results are shown in Table 2.
[0032] Table 2 Performance Comparison (Changing PLA and EVA Doses)
[0033] As shown in Table 2, with the increase of EVA content in the formula, PLA content decreases, the tensile strength of the material decreases, while the elongation at break and notched impact strength increase, i.e., toughness increases.
[0034] Example 4 The difference from Example 2 is that 0.6 parts of DCP and 0.3 parts of trimethylolpropane trimethacrylate (TMPTMA) are used, while the rest are the same as in Example 2.
[0035] The resulting material has a tensile strength of 15.1 MPa, an elongation at break of 302%, and a notched impact strength of 24.3 KJ / m. 2 .
[0036] Example 5 The difference from Example 2 is that 0.8 parts of DCP and 0.4 parts of trimethylolpropane trimethacrylate (TMPTMA) are used, while the rest are the same as in Example 2.
[0037] The resulting material has a tensile strength of 13.9 MPa, an elongation at break of 389%, and a notched impact strength of 29.2 KJ / m. 2 .
[0038] Performance tests were conducted on Examples 2, 4, and 5, and the test results are shown in Table 3.
[0039] Table 3 Performance Comparison (Changing the Amount of Crosslinking System)
[0040] As shown in Table 3, within a certain range, the toughness of the material increases with the increase of the cross-linking system content.
[0041] Example 6 The difference from Example 1 is that triallyl isocyanurate (TAIC) is used instead of trimethylolpropane trimethacrylate, otherwise the same as in Example 1.
[0042] The resulting material has a tensile strength of 17.5 MPa, an elongation at break of 243%, and a notched impact strength of 16.8 KJ / m. 2 .
[0043] Example 7 The difference from Example 1 is that divinylbenzene is used instead of trimethylolpropane trimethacrylate, otherwise the same as in Example 1.
[0044] The resulting material has a tensile strength of 16.1 MPa, an elongation at break of 224%, and a notched impact strength of 13.6 KJ / m. 2 .
[0045] Comparative Example 1 (without dynamic vulcanization) The difference from Example 2 is that DCP and TMPTMA are not added, and their proportions are replaced by PLA and EVA in proportion (PLA increases by 0.5 parts, EVA increases by 0.1 parts). The rest of the steps are the same.
[0046] The resulting material has a tensile strength of 9.3 MPa, an elongation at break of 140%, and a notched impact strength of 7.2 KJ / m. 2 .
[0047] Comparative Example 2 (without attapulgite) The difference from Example 2 is that AT is not added, and its proportion is replaced by PLA and EVA proportionally (PLA increases by 3.4 parts, and EVA increases by 0.6 parts), while the rest of the steps are the same.
[0048] The material has a tensile strength of 12.1 MPa, an elongation at break of 170%, and a notched impact strength of 8.7 KJ / m. 2 .
[0049] Comparative Example 3 The difference between this comparative example and Example 1 is that the EAA content in the raw materials is replaced from 2 parts to 6 parts, while the rest of the steps are the same as in Example 1.
[0050] The resulting material has a tensile strength of 26.7 MPa, an elongation at break of 132%, and a notched impact strength of 11.9 KJ / m. 2 .
[0051] Comparative Example 4 The difference between this comparative example and Example 1 is that the EAA content in the raw materials is replaced from 2 parts to 1 part, while the rest of the steps are the same as in Example 1.
[0052] The resulting material has a tensile strength of 16.4 MPa, an elongation at break of 157%, and a notched impact strength of 13.4 KJ / m. 2 .
[0053] Comparative Example 5 The difference between this comparative example and Example 1 is that the raw material EAA is replaced with PE-g-MAH (maleic anhydride-grafted polyethylene), while the rest of the steps are the same as in Example 1.
[0054] The resulting material has a tensile strength of 15.9 MPa, an elongation at break of 149%, and a notched impact strength of 12.8 KJ / m. 2 .
[0055] Comparative Example 6 The difference between this comparative example and Example 1 is that the raw material AT is replaced with nano-calcium carbonate, while the rest of the steps are the same as in Example 1.
[0056] The resulting material has a tensile strength of 15.4 MPa, an elongation at break of 176%, and a notched impact strength of 13.9 KJ / m. 2 .
[0057] Performance tests were conducted on the examples and comparative examples, and the results are shown in Table 4.
[0058] Table 4 Performance Comparison (with Changed Components)
[0059] This invention employs dynamic vulcanization and attapulgite synergistic modification of a polylactic acid / ethylene-vinyl acetate copolymer system. Dynamic vulcanization enables in-situ crosslinking of EVA to form elastic microdomains, constructing a stable "sea-island" structure that significantly improves toughness and elongation at break. Attapulgite, with its nanofiber morphology, plays a role in interfacial bridging and compatibilization, inhibiting phase region coarsening and strengthening interfacial bonding. The synergistic effect of both achieves chemical crosslinking and inorganic reinforcement coupling, significantly improving impact toughness while maintaining high strength, thus solving the problem of polylactic acid's high brittleness and difficulty in achieving both strength and toughness.
[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.
Claims
1. A composite material prepared based on dynamic vulcanization, characterized in that: The composite material is composed of polylactic acid, ethylene-vinyl acetate copolymer, attapulgite, peroxide crosslinking agent, co-crosslinking agent, antioxidant and compatibilizer; The composition, by mass parts, is as follows: polylactic acid 80-95 parts; ethylene-vinyl acetate copolymer 5-20 parts; attapulgite 1-5 parts; peroxide crosslinking agent 0.2-2 parts; co-crosslinking agent 0.1-1 parts; antioxidant 0.1-0.5 parts; and compatibilizer 1-5 parts.
2. The composite material prepared based on dynamic vulcanization as described in claim 1, characterized in that: By mass parts, polylactic acid is 80-95 parts; ethylene-vinyl acetate copolymer is 10-15 parts; attapulgite is 2-5 parts; peroxide crosslinking agent is 0.5-1.5 parts; co-crosslinking agent is 0.2-0.8 parts; antioxidant is 0.2-0.4 parts; and compatibilizer is 2-4 parts.
3. The composite material prepared based on dynamic vulcanization as described in claim 2, characterized in that: By mass, the composition is as follows: polylactic acid 85 parts; ethylene-vinyl acetate copolymer 15 parts; attapulgite 4 parts; peroxide crosslinking agent 0.8 parts; co-crosslinking agent 0.6 parts; antioxidant 1 part; and compatibilizer 4 parts.
4. The composite material prepared based on dynamic vulcanization as described in claim 1, characterized in that: The peroxide crosslinking agent includes one or more of dicumyl peroxide, benzoyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.
5. The composite material prepared by dynamic vulcanization as described in claim 1, characterized in that: The co-crosslinking agent includes one or more of trimethylolpropane trimethacrylate, triallyl isocyanurate, and divinylbenzene.
6. The composite material prepared based on dynamic vulcanization as described in claim 1, characterized in that: The compatibilizer includes one or more of ethylene-acrylic acid copolymers and epoxy-functionalized styrene-vinyl acetate copolymers.
7. The method for preparing composite materials based on dynamic vulcanization as described in any one of claims 1 to 6, characterized in that: The process includes: weighing each component according to the mass fractions specified in any one of claims 1 to 3; vacuum drying polylactic acid, ethylene-vinyl acetate copolymer, and attapulgite; adding polylactic acid, ethylene-vinyl acetate copolymer, attapulgite, compatibilizer, and antioxidant to a twin-screw extruder; injecting a premixed solution of peroxide crosslinking agent and co-crosslinking agent through a side feed port during the 2nd to 4th minute of blending; continuing the dynamic vulcanization reaction for 2 to 5 minutes to achieve in-situ crosslinking of the EVA phase; extruding, water cooling, and pelletizing to obtain the thermoplastic composite material.
8. The preparation method according to claim 7, characterized in that: The vacuum drying conditions for PLA are 60–80℃ for 8–12 h, for EVA it is 50–70℃ for 6–8 h, and for AT it is 100–110℃ for 3–5 h.
9. The preparation method according to claim 7, characterized in that: The melt blending temperature is 160–180℃.
10. The preparation method according to claim 7, characterized in that: The premixed liquid is prepared by pre-dispersing a peroxide crosslinking agent and a co-crosslinking agent in epoxidized soybean oil to form a premixed liquid with a mass concentration of 30-60%.