Multifunctional auxiliary agent based on dual grafting, preparation method and application of multifunctional auxiliary agent in sheet

Abstract

The invention discloses a multifunctional auxiliary agent based on dual grafting, a preparation method and application in a sheet, and relates to the technical field of high polymer material modification.The preparation method of the auxiliary agent comprises the following steps that S1, 4, 4-dicarboxylic acid diphenyl ether is dissolved in N, N-dimethylformamide, and chloroacetamide and triethylamine are added into the solution; s2, glycerol triglycidyl ether and zinc acetylacetonate are added for a reaction; s3, after the reaction, acrylic acid (3, 4-epoxy cyclohexyl) methyl ester is added for continuous reaction, and a grafting auxiliary agent precursor is obtained; s4, uniformly mixing PBAT, an initiator and the grafting auxiliary agent precursor, and performing melt extrusion to obtain PBAT-g-TCOE; and S5, uniformly mixing PBAT-g-TCOE, an initiator and PBS, and carrying out melt extrusion to obtain the multifunctional auxiliary agent. The auxiliary agent provided by the invention is simple in synthesis process, can overcome the problems of low nucleation efficiency and poor compatibility with PLA / PBAT of the existing auxiliary agent, and can significantly improve the compatibility between PLA and PBAT, thereby enhancing the mechanical and thermal properties of the PLA / PBAT composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material modification, and particularly relates to a multifunctional additive based on dual grafting, a preparation method thereof, and an application thereof in a sheet. Background Art

[0002] Polylactic acid (PLA), as one of the most promising biodegradable materials at present, has been put into use in the fields of disposable tableware and packaging. In addition, in the medical field, such as disposable infusion devices, surgical sutures, tissue repair materials, etc., there are also a large number of applications. However, PLA has defects such as poor toughness, easy bending and deformation, weak impact resistance and tearing resistance, slow crystallization rate, and poor thermal performance, which limit the application fields of PLA. Poly(butylene adipate-co-terephthalate) (PBAT), as a biodegradable plastic, has high flexibility, good ductility, and high processing stability, and can achieve complementary properties when blended with PLA. Therefore, PBAT can be used to toughen PLA. However, the compatibility between PLA and PBAT is not good. When the amount of PBAT is greater than 5%, the PLA / PBAT blend is prone to phase separation, which will deteriorate the performance of the blend system. Therefore, it is necessary to solve the compatibility problem between PLA and PBAT.

[0003] At present, regarding the toughening, nucleation, and compatibilization problems of the PLA / PBAT system, the main methods include plasticizing and modifying PLA / PBAT, as well as adding nucleating agents and compatibilizers. For example, the plasticizer tributyl acetylcitrate (ATBC) plays a key role in the PLA / PBAT composite material, especially in improving the mechanical properties and processing properties of the material. For the PLA / PBAT composite material prepared by the melt blending method, adding ATBC and epoxidized soybean oil (ESO) to it can improve the tensile strength and elongation at break of the composite material while maintaining good biodegradability. However, such plasticizers have deficiencies such as a large addition amount, easy migration, and easy adhesion to the machine surface, resulting in the performance of the PLA / PBAT composite material not being durable, and further causing a decrease in mechanical properties. Another example is that inorganic nucleating agents are inexpensive and rich in sources. Adding such nucleating agents to the PLA / PBAT composite material can increase the crystallization rate of PLA and PBAT and increase the density of crystal nuclei, thereby increasing the crystallinity. However, inorganic nucleating agents have poor compatibility with PLA / PBAT and low nucleation efficiency, and extensive use will affect the appearance quality and service performance of the product. Again, epoxy and isocyanate compatibilizers can be added to the PLA / PBAT system. Compared with the epoxy chain extender (ADR) series, isocyanate-based ones have high toxicity and limited applications. And ADR has 3-9 epoxy functional groups on the main chain, with low toxicity and good compatibilization effect. However, the ADR series of compatibilizers are expensive. Therefore, there is an urgent need to develop an additive that can significantly improve the interfacial compatibility and crystallization properties of PLA and PBAT, and improve the mechanical and thermal properties of the PLA / PBAT composite material. Summary of the Invention

[0004] Based on the technical problems existing in the background art, the present invention proposes a dual-grafting-based multifunctional additive, its preparation method, and application in sheets. The synthesis process of this additive is simple, which can overcome the problems of low nucleation efficiency and poor compatibility with PLA / PBAT of existing additives, and can significantly improve the compatibility between PLA and PBAT, thereby enhancing the mechanical and thermal properties of the PLA / PBAT composite material.

[0005] The preparation method of the dual-grafting-based multifunctional additive proposed by the present invention is as follows:

[0006] S1: React 4,4'-dicarboxydiphenyl ether, chloroacetamide, and triethylamine in N,N-dimethylformamide;

[0007] S2: Add glycerol triglycidyl ether and zinc acetylacetonate to the solution after the reaction in S1 for reaction;

[0008] S3: Add methyl (3,4-epoxycyclohexyl) acrylate to the solution after the reaction in S2 for reaction to obtain a grafted additive precursor;

[0009] S4: Melt-extrude poly(butylene adipate-co-terephthalate), initiator, and grafting aid precursor.

[0010] S5: Mix the melt-extruded product of S4 with initiator and poly(butylene succinate), and then melt-extrude again to obtain the multifunctional aid.

[0011] Preferably, the mass ratio of chloroacetamide, triethylamine, 4,4'-dicarboxydiphenyl ether, glycerol triglycidyl ether, (3,4-epoxycyclohexyl)methyl acrylate, and zinc acetylacetonate is 1:1 - 1.5:1 - 2:1 - 1.5:1.5 - 2.5:0.05 - 0.3.

[0012] Preferably, the reaction conditions in S1 are: temperature 70 - 110 °C, time 3 - 10 h.

[0013] Preferably, the reaction conditions in S2 and S3 are: temperature 50 - 100 °C, time 4 - 6 h.

[0014] Preferably, the mass ratio of poly(butylene adipate-co-terephthalate), initiator, and grafting aid precursor in S4 is 10:0.01 - 0.5:0.05 - 1; the conditions for melt-extrusion are: screw speed 200 - 400 r / min, feeding speed 3 - 8 r / min, and the extrusion temperature zones are set as 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C.

[0015] Preferably, the mass ratio of poly(butylene succinate), initiator, and the melt-extruded product of S4 in S5 is 2 - 8:0.01 - 0.5:10; the conditions for melt-extrusion are: screw speed 200 - 400 r / min, feeding speed 3 - 8 r / min, and the extrusion temperature zones are set as 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C.

[0016] Preferably, the initiator in S4 and S5 is one or more of diisopropyl peroxide, benzoyl peroxide, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hex-3-yne, and di(tert-butylperoxyisopropyl)benzene.

[0017] A multifunctional aid based on double grafting proposed by the present invention is prepared by the above preparation method.

[0018] A preparation method of a composite material proposed by the present invention is as follows: Mix poly(butylene adipate-co-terephthalate), polylactic acid, and the above multifunctional aid, and then melt-extrude to obtain the composite material.

[0019] Preferably, the mass ratio of polylactic acid, polybutylene adipate terephthalate and the multifunctional additive is 70-90:10-20:0.1-3; the conditions for melt extrusion are: the screw speed is 200-300 r / min, the feeding speed is 3-6 r / min, and the extrusion temperature zones are set at 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C.

[0020] Application of the above-mentioned composite material proposed by the present invention in sheets.

[0021] Advantageous technical effects of the present invention:

[0022] The present invention proposes a method of nucleophilic substitution - epoxy ring opening - dual grafting. Using chloroacetamide, 4,4'-dicarboxydiphenyl ether, glycerol triglycidyl ether, (3,4-epoxycyclohexyl)methyl acrylate, PBAT, and PBS as raw materials, a multifunctional additive is prepared; this substance is grafted with two tough polyesters and simultaneously has amide, hydroxyl, double bond, and epoxy functional groups, belonging to an integrated structure, which is significantly different from conventional PBAT or PLA grafts; this substance can not only rely on the high toughness and compatibility of the two-terminal polyesters, but also generate a variety of hydrogen bond and chemical bond crosslinking networks, so it can simultaneously exhibit multiple functions such as nucleation, compatibilization, and toughening in the PLA / PBAT system, thereby enhancing the mechanical and thermal properties of the PLA / PBAT composite material. Description of the Drawings

[0023] Figure 1 It is a FTIR comparison diagram of TCOE-1, PBAT, PBAT-g-TCOE-1, and PBAT-g-TCOE-g-PBS-1 proposed by the present invention;

[0024] Figure 2 It is a crystallization / melting curve comparison diagram of PLA / PBAT-1 and PLA / PBAT / PBAT-g-TCOE-g-PBS-1 proposed by the present invention; where (a) is the first cooling crystallization process and (b) is the second heating melting process;

[0025] Figure 3 It is a schematic diagram of the synthesis mechanism of PBAT-g-TCOE-g-PBS proposed by the present invention;

[0026] Figure 4 It is a schematic diagram of the action mechanism of PLA / PBAT / PBAT-g-TCOE-g-PBS proposed by the present invention. Detailed Embodiments

[0027] The present invention will be further explained below in conjunction with specific embodiments.

[0028] In the embodiments of the present invention, polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), chloroacetamide (CC), triglycidyl ether of glycerol (TPEG), 4,4'-oxybis(benzoic acid) (OBA), N,N-dimethylformamide (DMF), triethylamine (TEA), (3,4-epoxycyclohexyl)methyl acrylate (EMA), zinc acetylacetonate, poly(butylene succinate) (PBS), etc. are all commercially available.

[0029] Example 1

[0030] First, weigh 5 g of OBA and add it to 750 g of DMF to form a solution; then, transfer the above solution to a three-necked flask, and then drop 3.9 g of TEA to obtain a mixed solution; then, add 3.6 g of CC to the above mixed solution and stir and react at 85 °C for 8 h to obtain a solution denoted as CO-1.

[0031] Weigh 5 g of TPEG, suck it up with a dropper and drop it into the solution CO-1 at a rate of 1 drop per second; then, add 0.6 g of zinc acetylacetonate to the solution CO-1 and stir and react at 70 °C for 6 h to obtain a solution denoted as TCO-1.

[0032] Weigh 6 g of EMA, suck it up with a dropper and drop it into the solution TCO-1 at a rate of 1 drop per second; then, stir and react at 75 °C for 5 h to obtain a solution denoted as TCOE-1.

[0033] After cooling the solution TCOE-1, transfer it to a single-necked flask, perform rotary evaporation at 160 °C, take out the remaining part in the single-necked flask after no liquid drips out, dry this part in an oven at 100 °C for 4 h, then wash the dried solid with absolute ethanol for more than three times, and after the washing is completed, dry the obtained solid in the oven at 100 °C for 8 h to obtain the grafting aid precursor.

[0034] Weigh 120 g of PBAT, 3 g of diisopropylbenzene peroxide and 10 g of the grafting aid precursor and put them into a high-speed mixer, mix at 200 r / min for 10 min to obtain a solid mixture.

[0035] Put the above 133 g of solid mixture into a twin-screw extruder, set the screw speed to 200 r / min, the feeding speed to 6 r / min, and the extrusion temperature zones to 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C. After melting extrusion and cooling, dry at 80 °C for 12 h to obtain a product denoted as PBAT-g-TCOE-1.

[0036] Weigh 120 g of PBS, 3 g of dicumyl peroxide, and 60 g of PBAT-g-TCOE-1, put them into a high-speed mixer, mix them for 10 min under the condition of 200 r / min, then put the mixture into a twin-screw extruder, set the screw speed at 200 r / min, the feeding speed at 6 r / min, and the extrusion temperature zones at 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C. After melt extrusion and cooling, dry it at 80 °C for 12 h to obtain a multifunctional additive denoted as PBAT-g-TCOE-g-PBS-1.

[0037] Weigh 160 g of PBAT, 800 g of PLA, and 10 g of the multifunctional additive PBAT-g-TCOE-g-PBS-1, place them in a high-speed mixer, mix them at a speed of 500 r / min for 20 min to obtain a mixture; then, melt-extrude the mixture, set the screw speed at 200 r / min, the feeding speed at 6 r / min, and the extrusion temperature zones at 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C to obtain a composite material denoted as PLA / PBAT / PBAT-g-TCOE-g-PBS-1.

[0038] Example 2

[0039] Weigh 5.5 g of TPEG, suck it with a dropper and add it dropwise to solution CO-1 at a rate of 1 drop per second; then, add 0.6 g of zinc acetylacetonate to solution CO-1, stir and react at 70 °C for 6 h to obtain a solution denoted as TCO-2.

[0040] Weigh 6 g of EMA, suck it with a dropper and add it dropwise to solution TCO-2 at a rate of 1 drop per second; then, stir and react at 75 °C for 5 h to obtain a solution denoted as TCOE-2.

[0041] After cooling solution TCOE-2, transfer it to a single-neck flask, perform rotary evaporation at 160 °C. After rotary evaporation until no liquid drips out, take out the remaining part in the single-neck flask, dry this part in an oven at 100 °C for 4 h, then wash the dried solid with absolute ethanol for more than three times. After the washing is completed, dry the obtained solid in the oven at 100 °C for 8 h to obtain the grafting additive precursor.

[0042] Weigh 120 g of PBAT, 3 g of dicumyl peroxide and 10 g of grafting agent precursor, put them into a high-speed mixer, and mix for 10 min under the condition of 200 r / min to obtain a solid mixture.

[0043] Put the above 133 g of solid mixture into a twin-screw extruder, set the screw speed at 200 r / min, the feeding speed at 6 r / min, and the extrusion temperature zones at 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C. After melt extrusion and cooling, dry at 80 °C for 12 h to obtain the product denoted as PBAT-g-TCOE-2.

[0044] Weigh 120 g of PBS, 3 g of dicumyl peroxide and 60 g of PBAT-g-TCOE-2, put them into a high-speed mixer, and mix for 10 min under the condition of 200 r / min. Then put the mixture into a twin-screw extruder, set the screw speed at 200 r / min, the feeding speed at 6 r / min, and the extrusion temperature zones at 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C. After melt extrusion and cooling, dry at 80 °C for 12 h to obtain the multifunctional additive denoted as PBAT-g-TCOE-g-PBS-2.

[0045] Weigh 160 g of PBAT, 800 g of PLA and 10 g of the multifunctional additive PBAT-g-TCOE-g-PBS-2, put them into a high-speed mixer, and mix at a speed of 500 r / min for 20 min to obtain a mixture. Then, melt-extrude the mixture, set the screw speed at 200 r / min, the feeding speed at 6 r / min, and the extrusion temperature zones at 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C to obtain the composite material denoted as PLA / PBAT / PBAT-g-TCOE-gPBS-2.

[0046] Example 3

[0047] Weigh 4.5 g of TPEG, suck it up with a dropper and add it dropwise to solution CO-1 at a rate of 1 drop / second. Then, add 0.6 g of zinc acetylacetonate to solution CO-1 and stir and react at 70 °C for 6 h to obtain a solution denoted as TCO-3.

[0048] Weigh 6 g of EMA, suck it up with a dropper and add it dropwise to solution TCO-3 at a rate of 1 drop / second. Then, stir and react at 75 °C for 5 h to obtain a solution denoted as TCOE-3.

[0049] After cooling the solution TCOE-3, transfer it to a single-neck flask and perform rotary evaporation at 160 °C. After rotary evaporation until no liquid drips out, take out the remaining part in the single-neck flask, dry this part in an oven at 100 °C for 4 h, then wash the dried solid with anhydrous ethanol for more than three times. After the washing is completed, dry the obtained solid in an oven at 100 °C for 8 h to obtain the grafting aid precursor.

[0050] Weigh 120 g of PBAT, 3 g of diisopropylbenzene peroxide and 10 g of the grafting aid precursor, put them into a high-speed mixer, and mix at 200 r / min for 10 min to obtain a solid mixture.

[0051] Place the above 133 g of solid mixture in a twin-screw extruder, set the screw speed to 200 r / min, the feeding speed to 6 r / min, and the extrusion temperature zones to 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C. After melt extrusion and cooling, dry at 80 °C for 12 h to obtain the product denoted as PBAT-g-TCOE-3.

[0052] Weigh 120 g of PBS, 3 g of diisopropylbenzene peroxide and 60 g of PBAT-g-TCOE-3, put them into a high-speed mixer, and mix at 200 r / min for 10 min. Then put the mixture into a twin-screw extruder, set the screw speed to 200 r / min, the feeding speed to 6 r / min, and the extrusion temperature zones to 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C. After melt extrusion and cooling, dry at 80 °C for 12 h to obtain the multifunctional aid denoted as PBAT-g-TCOE-g-PBS-3.

[0053] Weigh 160 g of PBAT, 800 g of PLA and 10 g of the multifunctional aid PBAT-g-TCOE-g-PBS-3, place them in a high-speed mixer, and mix at a speed of 500 r / min for 20 min to obtain a mixture; then, melt-extrude the mixture, set the screw speed to 200 r / min, the feeding speed to 6 r / min, and the extrusion temperature zones to 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C to obtain the composite material denoted as PLA / PBAT / PBAT-g-TCOE-g-PBS-3.

[0054] Comparative Example 1

[0055] Weigh 160 g of PBAT and 800 g of PLA and place them in a high-speed mixer. Mix them at a rotation speed of 500 r / min for 20 min to obtain a mixed material. Then, melt-extrude the mixed material. Set the screw rotation speed to 200 r / min, the feeding speed to 6 r / min, and the extrusion temperature zones to 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C to obtain a composite material denoted as PLA / PBAT-1.

[0056] Comparative Example 2

[0057] Weigh 160 g of PBAT, 800 g of PLA, and 10 g of PBAT-g-TCOE-1, and place them in a high-speed mixer. Mix them at a rotation speed of 500 r / min for 20 min to obtain a mixed material. Then, melt-extrude the mixed material. Set the screw rotation speed to 200 r / min, the feeding speed to 6 r / min, and the extrusion temperature zones to 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C to obtain a composite material denoted as PLA / PBAT / PBAT-g-TCOE-1.

[0058] The present invention conducts mechanical property tests on the samples prepared from pure PLA, Examples 1-3, and Comparative Examples 1-2, and the results are shown in Table 1.

[0059] Table 1 Mechanical Property Tests

[0060] As can be seen from Table 1, the pure PLA sample is hard and brittle. After adding PBAT, the tensile and flexural strengths decrease, but the elongation at break and impact strength increase. Generally speaking, the mechanical properties of PLA / PBAT / PBAT-g-TCOE-g-PBS are better than those of the PLA / PBAT sample. For the sample in Example 1, the tensile strength can reach 46.82 MPa, the elongation at break is 68%, the flexural strength is 47.68 MPa, the impact strength is 15.27 MPa, and the flexural modulus is 1423 MPa. The reason for the above phenomenon is that the interfacial compatibility between PLA and PBAT is poor, and direct blending will reduce the mechanical properties. However, when PBAT-g-TCOE-g-PBS is added, the mechanical properties of the PLA / PBAT sample are significantly improved. This is because PBAT-g-TCOE-g-PBS has good compatibility with PLA and PBAT, and can further enhance the compatibility and crystallization properties of PLA and PBAT by constructing hydrogen bond and chemical bond crosslinking networks, thereby improving the mechanical properties of the PLA / PBAT composite. It can also be seen from Examples 1-3 and Comparative Example 2 that when the mass ratio of TPEG, CC, OBA, and EMA is 5:3.6:5:6, the mechanical properties of the sample are the best, and the double-grafted PBAT-g-TCOE-g-PBS additive has better effects than PBAT-g-TCOE.

[0061] In the present invention, FTIR tests were carried out on PBAT, TCOE-1, PBAT-g-TCOE-1, and PBAT-g-TCOE-PBS-1, and the results are as Figure 1 shown. As Figure 1 can be seen, in the FTIR spectrum of TCOE-1, the stretching vibration absorption peak of C=C is at 1563 cm -1 . At the same time, compared with the FTIR spectrum of PBAT, the spectrum of PBAT-g-TCOE-1 shows the following significant characteristics: the symmetric C-O bond stretching vibration absorption peak of the epoxy group is at 956 cm -1 , and the peak at 1258 cm -1 is the asymmetric C-O bond stretching vibration absorption peak of the epoxy group, and the absorption peak at 3393 cm -1 is the stretching vibration peak of N-H. Based on the changes in the above spectral characteristics, it can be known that TCOE-1 has been successfully grafted onto PBAT. In addition, compared with the FTIR infrared spectrum of PBAT-g-TCOE-1, the C-H bending vibration peak at 727 cm -1 in PBAT-g-TCOE-g-PBS-1 is enhanced, and no new absorption peaks are generated. From this, it can be known that PBS has been successfully grafted onto PBAT-g-TCOE-1.

[0062] The present invention conducts differential scanning calorimetry tests on PLA / PBAT-1 and PLA / PBAT / PBAT-g-TCOE-g-PBS-1, and the results are as follows Figure 2 shown, where (a) is the first cooling crystallization process and (b) is the second heating melting process. The detailed thermodynamic parameters of the samples are shown in Table 2.

[0063] Table 2 Thermodynamic parameters of the samples

[0064] From Figure 2 (a) and Table 2, it can be seen that the crystallization peak of PLA / PBAT-1 is weak. After adding PBAT-g-TCOE-g-PBS-1 to the system, its crystallization temperature increases, the crystallization peak becomes stronger and approaches the high-temperature region. This is because during the cooling process, PBAT-g-TCOE-g-PBS-1 can provide crystal nuclei at a relatively high temperature and induce the molecular chains of PLA and PBAT to attach to them and grow, acting as a nucleating agent. From Figure 2 (b) and Table 2, it can also be seen that when PBAT-g-TCOE-g-PBS-1 is added to the system, the melting temperature increases, indicating that the addition of PBAT-g-TCOE-g-PBS-1 can enhance the thermal properties of the PLA / PBAT material.

[0065] Figure 3 is a schematic diagram of the synthesis mechanism of PBAT-g-TCOE-g-PBS proposed by the present invention. As Figure 3 shown, the present invention first uses OBA and CC to undergo a nucleophilic substitution reaction under the catalysis of TEA to obtain CO; then successively adds TPEG and EMA to CO, and conducts an epoxy group ring-opening reaction under the action of the catalyst zinc acetylacetonate to obtain a grafting aid precursor; finally, the grafting aid precursor is subjected to a double grafting reaction with PBAT and PBS under the action of an initiator to obtain PBAT-g-TCOE-g-PBS.

[0066] Figure 4 is a schematic diagram of the action mechanism of PLA / PBAT / PBAT-g-TCOE-g-PBS proposed by the present invention. PBAT-g-TCOE-g-PBS is grafted with two polyesters. PBAT and PBS have strong toughness and good compatibility, so PBAT-g-TCOE-g-PBS can significantly enhance the toughness of the PLA / PBAT composite material. As Figure 4As shown, the N-H and O-H in the PBAT-g-TCOE-g-PBS molecule will form hydrogen bonds with the oxygen atoms on PLA and PBAT, enhancing the interaction force between PBAT-g-TCOE-PBS and PLA and PBAT. Therefore, during the cooling crystallization process of the PLA / PBAT / PBAT-g-TCOE-g-PBS-1 sample, PBAT-g-TCOE-g-PBS-1 can provide crystal nuclei at a relatively high temperature, and induce the molecular chains of PLA and PBAT to closely adhere to it and grow through hydrogen bond interaction, thereby promoting crystallization. In addition, there are double bonds on the surface of the PBAT-g-TCOE-g-PBS molecule. During the melt blending process with PLA and PBAT, the epoxy functional groups in the PBAT-g-TCOE-g-PBS molecule will simultaneously undergo ring-opening reactions with the end groups of PLA and PBAT, thus improving the compatibility between PLA and PBAT.

[0067] Although the embodiments of the present application have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents, and all should be included within the protection scope of the present application.

Claims

1. A preparation method of a multifunctional auxiliary based on dual grafting, characterized in that, The method steps are as follows: S1: React 4,4'-dicarboxydiphenyl ether, chloroacetamide and triethylamine in N,N-dimethylformamide; S2: Add glycerol triglycidyl ether and zinc acetylacetonate to the solution after the reaction in S1 and react; S3: Add methyl (3,4-epoxycyclohexyl) acrylate to the solution after the reaction in S2 and react to obtain a grafting aid precursor; S4: Melt and extrude polybutylene adipate / terephthalate, an initiator and the grafting aid precursor; S5: Mix the melt-extruded product in S4 with an initiator and polybutylene succinate and then melt and extrude to obtain a multifunctionalized aid.

2. The preparation method of the dual-grafting-based multifunctional auxiliary according to claim 1, characterized in that, The mass ratio of chloroacetamide, triethylamine, 4,4'-dicarboxydiphenyl ether, glycerol triglycidyl ether, methyl (3,4-epoxycyclohexyl) acrylate and zinc acetylacetonate is 1:1 - 1.5:1 - 2:1 - 1.5:1.5 - 2.5:0.05 - 0.

3.

3. The preparation method of the dual-grafting-based multifunctional auxiliary agent according to claim 1, characterized in that, The reaction conditions in S1 are: temperature 70 - 110 °C, time 3 - 10 h; the reaction conditions in S2 and S3 are: temperature 50 - 100 °C, time 4 - 6 h.

4. The preparation method of the dual-grafting-based multifunctional auxiliary agent according to claim 1, characterized in that In S4, the mass ratio of polybutylene adipate / terephthalate, an initiator and the grafting aid precursor is 10:0.01 - 0.5:0.05 - 1; the conditions for melt extrusion are: the screw speed is 200 - 400 r / min, the feeding speed is 3 - 8 r / min, and the extrusion temperature zones are set at 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C.

5. The preparation method of the dual-grafting-based multifunctional additive according to claim 1, characterized in that, In S5, the mass ratio of polybutylene succinate, an initiator and the melt-extruded product in S4 is 2 - 8:0.01 - 0.5:10; the conditions for melt extrusion are: the screw speed is 200 - 400 r / min, the feeding speed is 3 - 8 r / min, and the extrusion temperature zones are set at 145, 145, 145, 150, 150, 150, 155, 155, 155, 155, 150, 150 °C.

6. The preparation method of the dual-grafting-based multifunctional auxiliary agent according to claim 1, characterized in that, The initiator in S4 and S5 is one or more of dicumyl peroxide, benzoyl peroxide, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hex-3-yne and di(tert-butylperoxyisopropyl)benzene.

7. A multifunctional auxiliary based on dual grafting, characterized in that Prepared by the preparation method described in any one of claims 1 - 6.

8. A method for preparing a composite material, characterized in that, The method steps are as follows: Mix polybutylene adipate / terephthalate, polylactic acid and the multifunctionalized aid described in claim 7 and then melt and extrude to obtain a composite material.

9. The method for preparing the composite material according to claim 8, wherein The mass ratio of polylactic acid, polybutylene adipate / terephthalate and the multifunctionalized aid is 70 - 90:10 - 20:0.1 - 3; the conditions for melt extrusion are: the screw speed is 200 - 300 r / min, the feeding speed is 3 - 6 r / min, and the extrusion temperature zones are set at 135, 140, 145, 150, 155, 160, 165, 165, 165, 165, 160, 155 °C.

10. Application of the composite material according to claim 8 or 9 in a sheet.

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