A degradable modified plastic and its application

Abstract

The invention discloses a degradable modified plastic and its application, belonging to the field of material engineering technology. The plastic comprises the following raw material components by weight: 30-50 parts of synthetic polymer, 20-30 parts of modified cellulose, 5-10 parts of dispersant, 5-10 parts of inorganic filler and 1-5 parts of compatibilizer. The plastic product prepared by the invention has excellent stability, fast degradation speed, no pollution to the environment, and excellent comprehensive mechanical properties, which can meet the requirements of plastic products such as garbage bags and packaging bags.

Description

Technical Field

[0001] The invention belongs to the technical field of material engineering, and in particular relates to a degradable modified plastic and application thereof. Background Art

[0002] Plastic is a polymer material with low density, high strength and corrosion resistance. It is widely used in industrial and agricultural production and the national defense industry. Plastic products made from it can be seen everywhere in our daily lives, providing great convenience for people's lives. However, with the increasing application scope and consumption of plastics, ordinary plastic waste in nature is accumulating at a rate of 25 million tons per year, most of which are disposable packaging products. They are light in weight, large in volume, difficult to degrade, and difficult and uneconomical to recycle. Moreover, waste plastics decompose very slowly in nature. It takes decades or even hundreds of years to completely decompose, causing environmental pollution. Therefore, the degradation and reuse of plastics is an urgent problem to be solved.

[0003] The degradable plastics currently under development and research are mainly divided into biodegradable plastics and photodegradable plastics. Biodegradable plastics can be divided into natural macromolecules, starch additives and chemically synthesized polymers. Among them, natural macromolecule biodegradable plastics have simple processing equipment, non-toxic and pollution-free degradation products, and are the most promising for development. However, most of the current degradable plastics still have problems such as slow degradation rate and insufficient material performance. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a degradable modified plastic and its application, which can effectively improve the degradation rate and mechanical properties such as toughness of the plastic.

[0005] To achieve the above purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0006] The object of the present invention is to provide a degradable modified plastic comprising the following raw material components in parts by weight:

[0007] 30-50 parts of synthetic polymer, 20-30 parts of modified cellulose, 5-10 parts of dispersant, 5-10 parts of inorganic filler and 1-5 parts of compatibilizer.

[0008] Further, the raw material components include the following parts by weight:

[0009] 40-50 parts of synthetic polymer, 25-30 parts of modified cellulose, 5-8 parts of dispersant, 5-8 parts of inorganic filler and 1-3 parts of compatibilizer.

[0010] Further, the preparation method of the modified fiber is as follows:

[0011] (1) placing a mixed solution of cellulose and a carbon source in a microwave environment of 500 to 800 W, heating at 300 to 500° C. for 2 to 5 hours, and then cooling, washing, and drying to obtain activated cellulose;

[0012] (2) mixing an imidazole compound, a silane coupling agent and the activated cellulose prepared in step (1), adding an organic solvent, reacting under a protective gas atmosphere, and heating to volatilize the organic solvent after the reaction to obtain modified cellulose.

[0013] Furthermore, the mass ratio of cellulose to carbon source is 1:0.5-1.

[0014] Furthermore, the cellulose is starch-based cellulose, wood cellulose, carboxymethyl cellulose, nitrocellulose or carboxypropyl methyl cellulose; and the carbon source is urea, triethanolamine or diethylamine.

[0015] Furthermore, the mass ratio of the imidazole compound to the activated cellulose is 0.1-0.5:1-2.

[0016] Furthermore, the imidazole compound is 1-chloroformyl-2-imidazolidinone, 2-phenylimidazole, 2-methylimidazole or 2-isopropylimidazole.

[0017] Furthermore, the silane coupling agent is chloromethyltriethoxysilane, 2-chloroethyltriethoxysilane, γ-chloropropyltriethoxysilane or γ-chloropropyltrimethoxysilane.

[0018] Furthermore, the organic solvent is anhydrous methanol, ethanol, isopropanol, acetone or epichlorohydrin.

[0019] Furthermore, the synthetic polymer is polylactic acid, polypropylene, polyethylene, polyvinyl chloride or polyacrylic acid.

[0020] Furthermore, the dispersant is liquid paraffin or glycerol; and the inorganic filler is calcium carbonate.

[0021] Another object of the present invention is to provide a method for preparing the above-mentioned degradable modified plastic, the process of which is: after uniformly mixing the components according to the formula, the modified plastic is obtained by a blow molding machine.

[0022] Another object of the present invention is to provide the use of the above-mentioned degradable modified plastic in the preparation of plastic products.

[0023] Beneficial effects of the present invention:

[0024] 1. The present invention activates cellulose by microwave treatment. After the activated cellulose is coupled with imidazole compounds, it is more conducive to the exposure of degradation active sites in the obtained plastic products, so as to further accelerate the degradation of plastics. In addition, a carbon source is added during the treatment process. The carbon source contains amino groups, which can increase the biological enzyme action sites of the material and improve the compatibility. Moreover, the introduction of amino groups can improve the cross-linking reaction ability of cellulose with other components, give full play to the reinforcing effect, and increase the biodegradability of the composite material.

[0025] 2. The present invention can accelerate the degradation efficiency of plastics by introducing imidazole bio-enzyme active sites on activated cellulose, and activated cellulose is more conducive to the exposure of enzyme active sites, thereby increasing the degradation rate of plastic products. The degradation rate can be significantly increased by combining with inorganic fillers and other ingredients.

[0026] 3. The present invention introduces imidazole and amino groups into cellulose, which can not only significantly increase the degradation rate of plastics, but also enhance the binding force between cellulose and synthetic polymers such as polylactic acid and polypropylene, and further enhance the mechanical strength of the product. Therefore, the plastic prepared by the present invention not only has good mechanical properties, but also has excellent biodegradability. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0028] Embodiment 1:

[0029] A degradable modified plastic comprises the following raw material components in parts by weight:

[0030] 30 parts of polylactic acid, 20 parts of modified cellulose, 5 parts of glycerol, 5 parts of calcium carbonate and 1 part of compatibilizer.

[0031] Wherein, the preparation method of modified cellulose is as follows:

[0032] (1) Carboxymethyl cellulose and triethanolamine are mixed in a mass ratio of 1:0.5, water is added to form a solution, and then placed in an 800 W microwave environment, heated at 350° C. for 2.5 h, and then cooled, washed, and dried to obtain activated cellulose;

[0033] (2) 2-phenylimidazole, 2-chloroethyltriethoxysilane and the activated cellulose prepared in step (1) are mixed, an organic solvent is added to dissolve, and the mixture is reacted for 2 hours under a protective gas atmosphere, wherein the mass ratio of 2-phenylimidazole to activated cellulose is 0.5:1. After the reaction is completed, the organic solvent is heated to evaporate, thereby obtaining modified cellulose.

[0034] Embodiment 2:

[0035] A degradable modified plastic comprises the following raw material components in parts by weight:

[0036] Polypropylene, 50 parts, modified cellulose 30 parts, glycerol 10 parts, calcium carbonate 10 parts and compatibilizer 5 parts.

[0037] Wherein, the preparation method of modified cellulose is as follows:

[0038] (1) Carboxymethyl cellulose and diethylamine are mixed in a mass ratio of 1:1, water is added to form a solution, and then placed in a 600 W microwave environment, heated at 400 ° C for 5 h, and then cooled, washed, and dried to obtain activated cellulose;

[0039] (2) 1-chloroformyl-2-imidazolidinone, γ-chloropropyltrimethoxysilane and the activated cellulose prepared in step (1) are mixed, an organic solvent is added to dissolve, and the mixture is reacted for 3 hours under a protective gas atmosphere, wherein the mass ratio of 1-chloroformyl-2-imidazolidinone to the activated cellulose is 0.1:1. After the reaction is completed, the organic solvent is heated to evaporate, thereby obtaining modified cellulose.

[0040] Embodiment 3:

[0041] A degradable modified plastic comprises the following raw material components in parts by weight:

[0042] 40 parts of polyacrylic acid, 250 parts of modified cellulose, 8 parts of glycerol, 6 parts of calcium carbonate and 3 parts of compatibilizer.

[0043] Wherein, the preparation method of modified cellulose is as follows:

[0044] (1) mixing lignocellulose and diethylamine at a mass ratio of 1:0.8, adding water to form a solution, placing the solution in a 500 W microwave environment, heating it at 450° C. for 3 h, and then cooling, washing, and drying to obtain activated cellulose;

[0045] (2) 1-chloroformyl-2-imidazolidinone, chloromethyltriethoxysilane and the activated cellulose prepared in step (1) are mixed, an organic solvent is added to dissolve, and the mixture is reacted for 2 hours under a protective gas atmosphere, wherein the mass ratio of 1-chloroformyl-2-imidazolidinone to the activated cellulose is 0.5:2. After the reaction is completed, the organic solvent is heated to evaporate, thereby obtaining modified cellulose.

[0046] Comparative Example 1:

[0047] Compared with Example 1, the difference is that the cellulose is not treated with microwaves, and the rest of the process is consistent with Example 1.

[0048] Comparative Example 2:

[0049] Compared with Example 1, the difference is that the microwave-treated cellulose, carbon source and imidazole compound do not form a modified complex, and are added to the formula separately, and the rest of the process remains the same as Example 1.

[0050] Comparative Example 3:

[0051] Compared with Example 1, the difference is that other types of degradation promoters are used to replace the modified cellulose, such as titanium dioxide, and the rest of the process is consistent with Example 1.

[0052] Comparative Example 4:

[0053] Compared with Example 1, the difference is that other types of degradation accelerators are used to replace the imidazole compounds to prepare the modified cellulose, such as titanium dioxide, and the rest of the process is consistent with Example 1.

[0054] Experimental example:

[0055] 1. Degradation experiment

[0056] The products obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were cut into a size of 20×20 cm and buried in soil. The biodegradation rates were tested after two weeks. The results are shown in Table 1.

[0057] Table 1 Biodegradation rate

[0058]

[0059] 2. Mechanical properties test

[0060] The products obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were cut into a size of 10×10 cm, and their tensile strength and elongation at break were tested. The results are shown in Table 2.

[0061] Table 2 Tensile strength and elongation at break

[0062]

[0063] According to the test results of Table 1 and Table 2, it can be seen that compared with Comparative Examples 1 to 4, the plastics prepared by the technical solution of the present invention have more excellent biodegradability and mechanical properties. After the key components such as modified cellulose in the formula of Comparative Examples 1 to 4 are replaced, the biodegradation rate and mechanical properties of the prepared plastic products are significantly reduced. Even if a degradation promoter that can improve the degradation efficiency, such as titanium dioxide, is used, the same technical effect as this solution cannot be achieved. It shows that the plastic products prepared by the present invention have excellent stability, fast degradation speed, no pollution to the environment, and excellent comprehensive mechanical properties, which can meet the requirements of plastic products such as garbage bags and packaging bags.

[0064] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A degradable modified plastic, characterized in that: The invention comprises the following raw material components in parts by weight: 30-50 parts of synthetic polymer, 20-30 parts of modified cellulose, 5-10 parts of dispersant, 5-10 parts of inorganic filler and 1-5 parts of compatibilizer.

2. The degradable modified plastic according to claim 1, characterized in that: The invention comprises the following raw material components in parts by weight: 40-50 parts of synthetic polymer, 25-30 parts of modified cellulose, 5-8 parts of dispersant, 5-8 parts of inorganic filler and 1-3 parts of compatibilizer.

3. The degradable modified plastic according to claim 1 or 2, characterized in that: The preparation method of the modified fiber is as follows: (1) placing a mixed solution of cellulose and a carbon source in a microwave environment of 500 to 800 W, heating at 300 to 500° C. for 2 to 5 hours, and then cooling, washing, and drying to obtain activated cellulose; (2) mixing an imidazole compound, a silane coupling agent and the activated cellulose prepared in step (1), adding an organic solvent, reacting under a protective gas atmosphere, and heating to volatilize the organic solvent after the reaction to obtain modified cellulose.

4. The degradable modified plastic according to claim 3, characterized in that: The mass ratio of the cellulose to the carbon source is 1:0.5-1.

5. The degradable modified plastic according to claim 3 or 4, characterized in that: The cellulose is starch-based cellulose, wood cellulose, carboxymethyl cellulose, nitrocellulose or carboxypropyl methyl cellulose; and the carbon source is urea, triethanolamine or diethylamine.

6. The degradable modified plastic according to claim 3, characterized in that: The mass ratio of the imidazole compound to the activated cellulose is 0.1-0.5:1-2.

7. The degradable modified plastic according to claim 3 or 6, characterized in that: The imidazole compound is 1-chloroformyl-2-imidazolidinone, 2-phenylimidazole, 2-methylimidazole or 2-isopropylimidazole.

8. The degradable modified plastic according to claim 1 or 2, characterized in that: The dispersant is liquid paraffin or glycerin; the inorganic filler is calcium carbonate.

9. A method for preparing the degradable modified plastic according to any one of claims 1 to 8, characterized in that: After the components are uniformly mixed according to the formula, the modified plastic is obtained by a blow molding machine.

10. Use of the degradable modified plastic according to any one of claims 1 to 8 in the preparation of plastic products.

Images