CN116102686A - Co-grafted functional polylactic acid material and preparation method thereof - Google Patents

Abstract

The application discloses a co-grafted functional polylactic acid material and a preparation method thereof. In the technical scheme, the method comprises the process of plasticizing polylactic acid, and the viscosity of the polylactic acid is reduced by using the plasticizer, so that the grafting auxiliary agent is uniformly distributed; the initiator is added in two steps in the melt mixing process, and the initiator is uniformly premixed with the anhydride or the epoxy-containing monomer, so that the grafting efficiency of the anhydride and the epoxy-containing monomer is effectively improved; by changing the types and the amounts of the anhydride monomers and the epoxy alkene-containing monomers, the functionalized polylactic acid materials with different grafting levels and different structures can be prepared.

Description

Co-grafted functional polylactic acid material and preparation method thereof

Technical Field

The application relates to the technical field of PLA modification, in particular to a co-grafted functional polylactic acid material and a preparation method thereof.

Background

With the exhaustion of petroleum resources and the gradual importance of people on ecological environment protection, the exploration of novel resources becomes quite important

Important. Polylactic acid (PLA) is a biodegradable polyester material, raw material lactic acid for synthesizing the polylactic acid is derived from natural crops such as corn, and the product can be degraded into water and carbon dioxide in natural environment after being abandoned, and in addition, the polylactic acid has good biocompatibility, excellent mechanical property and excellent processability, and can be processed by adopting technologies such as extrusion molding, injection molding, film blowing and the like. Therefore, the polylactic acid has good application prospect in the fields of disposable tableware, packaging materials, medical health and the like.

PLA is incompatible with most polymers in thermodynamics, in order to obtain PLA blending materials with excellent performance, an effective compatilizer is needed to be added in the polymer blending process for compatibilization, and more interfacial compatilizers are generally used as graft copolymers of polylactic acid and maleic anhydride or styrene, for example, the patent publication No. CN201610054571.2 is a preparation method of polylactic acid graft copolymer, polylactic acid is used as a raw material, and graft monomers such as maleic anhydride and butyl acrylate react with PLA under the action of an initiator, so that the prepared graft copolymer not only has the effect of interfacial compatibilization, but also can be used as functional polymer materials such as interfacial compatilizer of polylactic acid-based composite materials. Patent publication number CN101200579a discloses that the binding capacity of PLA to natural fibers is improved by grafting maleic anhydride modification of the polylactic acid matrix by melt grafting.

In the related art, the PLA grafting modification mostly adopts two modes of solution grafting reaction and melt grafting reaction, the solution method for preparing the PLA grafting copolymer has low efficiency, large solvent consumption and environmental pollution. The melt grafting method has simple process, but the grafting rate of the product is lower.

Disclosure of Invention

Therefore, the co-grafting functionalized polylactic acid material and the preparation method thereof can greatly improve the grafting rate.

It is widely appreciated that in the related art, the current PLA grafting modification mostly adopts two modes of solution grafting reaction and melt grafting reaction, and the solution method is low in preparation efficiency of PLA grafted copolymer, large in solvent consumption and environment-friendly. The melt grafting method has simple process, but the grafting rate of the product is lower.

Based on the problem, the inventor aims to overcome the technical defects, and the invention provides a preparation method of a co-grafted functional polylactic acid material, which can prepare functional polylactic acid materials with different structures and different grafting levels by adjusting the types and the dosage of anhydride and epoxy-containing monomers. Can also be used as a compatilizer between different systems.

Based on this, the present invention has been created.

In a first aspect, the present application provides a co-grafted functionalized polylactic acid material, which comprises the following raw materials in parts by weight:

suitably, but not limited to, the epoxy-containing monomer is one or any of glycidyl methacrylate, 1, 2-epoxy-5-hexene, 4- (epoxyethyl) styrene, 2, 3-epoxypropyl acrylate, allyl glycidyl ether.

Suitably, but not limited to, the anhydride is one or any of maleic anhydride, allyl succinic anhydride, (2-methyl-2-propene) succinic anhydride, (but-3-en-1-yl) succinic anhydride, 1, 4-cyclohexadiene-1, 2-dicarboxylic anhydride, 3-methyltetrahydrophthalic anhydride.

Suitably, but not limited to, the plasticizer is one or any of a lactic acid oligomer, a vegetable oil-based plasticizer, a citrate-based plasticizer.

Suitably, but not limited to, the grafting aid is one or any of vinyl monomers such as styrene, vinyl acetate, methyl acrylate, methyl methacrylate, acrylonitrile and the like.

Suitably, but not limited to, the initiator is one or any of benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, azobisisobutyronitrile.

In a second aspect, the present application provides a method for preparing a co-grafted functionalized polylactic acid material as described above, comprising the steps of:

s1, uniformly mixing anhydride and an initiator;

s2, uniformly mixing the epoxy-containing monomer with an initiator;

s3, fully melting the polylactic acid, the plasticizer and the grafting auxiliary premix, and then adding the anhydride and the initiator premix for melt mixing;

s4, adding a premix containing epoxy alkene monomers and an initiator on the basis of the step S3, and carrying out melt mixing to obtain the co-grafting functional polylactic acid material.

Suitably, but not limitatively, in step S3), the heating temperature of the melt is 180 to 220 ℃.

Compared with the related art, the method has the following beneficial effects:

the co-grafted functional polylactic acid material is modified by multiple functional groups, and the modification effect is better than that of single functional group modification; the grafting rate is controllable in a certain range, and the co-grafting functional polylactic acid products with different grafting levels can be prepared by changing the dosage of the anhydride monomers and the glycidyl methacrylate, so that the compatibility requirement of polylactic acid, polyester materials and polar materials is met, and the method is suitable for different application fields; the preparation process is simple, the production is convenient, and the cost is low.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below in connection with the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

In the description of the present application, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or an implicit indication of the number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. Furthermore, the present application may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not in themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize the application of other processes and/or the use of other materials.

Example 1

The co-grafting functional polylactic acid material and the preparation method thereof are prepared from the following raw materials in parts by weight:

firstly, fully melting a polylactic acid, a plasticizer and a grafting auxiliary premix, adding anhydride and 0.3 part of an initiator premix, fully mixing for 2min, adding an epoxy monomer and 0.7 part of a free radical initiator premix, and fully reacting for 5min to obtain the co-grafted functional polylactic acid material. The total grafting rate of the obtained co-grafted functional polylactic acid is 6.4 percent, and the tensile strength is 66.3MPa.

Example 2

The co-grafting functional polylactic acid material and the preparation method thereof are prepared from the following raw materials in parts by weight:

firstly, fully melting a polylactic acid, a plasticizer and a grafting auxiliary premix, adding anhydride and 0.2 part of an initiator premix, fully mixing for 2min, adding an epoxy monomer and 0.3 part of a free radical initiator premix, fully reacting for 5min, and obtaining the co-grafted functional polylactic acid material, and purifying and drying. The total grafting rate of the obtained co-grafted functional polylactic acid is 3.9 percent, and the tensile strength is 49.6MPa.

Example 3

The co-grafting functional polylactic acid material and the preparation method thereof are prepared from the following raw materials in parts by weight:

firstly, fully melting a polylactic acid, a plasticizer and a grafting auxiliary premix, adding anhydride and 0.5 part of an initiator premix, fully mixing for 2min, adding an epoxy monomer and 1 part of a free radical initiator premix, fully reacting for 5min, and obtaining the co-grafted functional polylactic acid material, and purifying and drying. The total grafting rate of the obtained co-grafted functional polylactic acid is 3.5 percent, and the tensile strength is 53.2MPa.

Comparative example 1

The only difference from example 1 is that the anhydride is phthalic anhydride, which is added in an amount of 0.5 parts.

The total grafting rate of the obtained co-grafted functional polylactic acid is 1.7%, and the tensile strength is 58MPa.

Comparative example 2

The only difference from example 1 is that the alkylene oxide-containing monomer is epoxybutene, which is added in an amount of 4 parts.

The total grafting rate of the obtained co-grafted functional polylactic acid is 1.1 percent, and the tensile strength is 35.3MPa.

The foregoing is merely a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present application should be covered by the scope of the present application.

Claims (8)

1. The co-grafted functional polylactic acid material is characterized by comprising the following raw materials in parts by weight:

2. the co-grafted functional polylactic acid material according to claim 1, wherein the epoxy-containing monomer is one or more of glycidyl methacrylate, 1, 2-epoxy-5-hexene, 4- (epoxy ethyl) styrene, 2, 3-epoxypropyl acrylate and allyl glycidyl ether.

3. The co-grafted functional polylactic acid material according to claim 1, wherein the acid anhydride is one or more of maleic anhydride, allyl succinic anhydride, (2-methyl-2-propylene) succinic anhydride, (but-3-en-1-yl) succinic anhydride, 1, 4-cyclohexadiene-1, 2-dicarboxylic anhydride, and 3-methyltetrahydrophthalic anhydride.

4. The co-grafted functionalized polylactic acid material according to claim 1, wherein the plasticizer is one or any of a lactic acid oligomer, a vegetable oil-based plasticizer, and a citrate plasticizer.

5. The co-grafted functional polylactic acid material according to claim 1, wherein the grafting aid is one or more of vinyl monomers such as styrene, vinyl acetate, methyl acrylate, methyl methacrylate, acrylonitrile and the like.

6. The co-grafted functional polylactic acid material according to claim 1, wherein the initiator is one or more of benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, and azobisisobutyronitrile.

7. A method for preparing the co-grafted functionalized polylactic acid material according to claim 1, comprising the following steps:

s1, uniformly mixing anhydride and an initiator;

s2, uniformly mixing the epoxy-containing monomer with an initiator;

s3, fully melting the polylactic acid, the plasticizer and the grafting auxiliary premix, and then adding the anhydride and the initiator premix for melt mixing;

s4, adding a premix containing epoxy alkene monomers and an initiator on the basis of the step S3, and carrying out melt mixing to obtain the co-grafting functional polylactic acid material.

8. The process according to claim 7, wherein in step S3), the heating temperature for melting is 180 to 220 ℃.