Biological environment-friendly plastic based on cockroach body waste and preparation method of biological environment-friendly plastic

Abstract

The invention provides a biological environment-friendly plastic based on cockroach body waste and a preparation method thereof. The biological environment-friendly plastic comprises the following components in parts by weight: 30-50 parts of cockroach protein, 10-20 parts of modified polylactic acid, 5-15 parts of a plasticizer and 1-5 parts of an adhesive. The biological environment-friendly plastic based on the cockroach body waste provided by the invention has relatively high tensile strength and elongation at break, which indicates that the biological environment-friendly plastic is good in mechanical property, easy to process and form and relatively high in sample weight loss ratio in a relatively short period, so that the biological environment-friendly plastic is relatively good in degradation property, free of pollution and environment-friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of bioplastics, and in particular relates to a bio-environmentally friendly plastic based on cockroach body waste and a preparation method thereof. Background Art

[0002] Plastics are ubiquitous products in daily life. They have the advantages of good tolerance, light weight, and easy availability. They are widely used in agriculture, medical care, packaging, automobiles, and electronics. According to the raw materials of plastics, they can be divided into petroleum-based plastics and bio-based plastics. Among them, petroleum-based plastics are of various types and widely used, but due to their large molecular weight, most of them are difficult to be completely degraded by nature. Therefore, after use, petroleum-based plastics enter the ecological environment in various forms due to lack of timely collection and thorough treatment, thus posing a threat to animal and human health. Bio-based plastics refer to a type of degradable plastic that is decomposed by the action of microorganisms such as bacteria, fungi, algae, and enzymes under natural conditions. This type of degradable plastic has excellent performance during use, and can be quickly hydrolyzed and degraded by enzymes or microorganisms after being discarded, thereby reducing greenhouse gas emissions and protecting environmental health.

[0003] Bio-based plastics are mainly divided into three categories: natural polymer materials, microbial synthetic polymer materials and artificial synthetic polymer materials. Among them, natural polymer materials such as starch, cellulose, lignin, chitin, protein, polysaccharides, etc. are abundant in source, low in price, safe and non-toxic, but their degradation ability needs to be improved. Microbial synthetic polymer materials are a type of polymer materials produced by microorganisms through fermentation of various carbon sources. Their advantages are that they can be completely biodegraded and the materials are easy to process and shape, but their heat resistance and mechanical properties after film formation are poor, and they are expensive. Artificial synthetic polymer materials refer to the use of chemical methods to synthesize biodegradable materials similar to natural polymer structures in order to give polymer materials excellent biodegradability, but their disadvantages are complex operations and poor economic benefits.

[0004] In view of the problems existing in the prior art, how to provide a bio-friendly plastic with excellent mechanical properties, good degradation performance and environmental friendliness is a problem to be solved urgently in the present invention. Summary of the invention

[0005] The object of the present invention is to provide a biological and environmentally friendly plastic based on cockroach body waste and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides a bio-environmentally friendly plastic based on cockroach body waste, characterized in that the bio-environmentally friendly plastic comprises the following components in parts by weight: 30-50 parts of cockroach body protein, 10-20 parts of modified polylactic acid, 5-15 parts of plasticizer, and 1-5 parts of adhesive;

[0007] The cockroach body protein is keratin;

[0008] The adhesive is a modified citrate.

[0009] As a further improvement, the extraction of keratin comprises the following steps:

[0010] (1) cleaning the cockroach shell and crushing it, then placing it in an alkaline solution and stirring it at 50-80° C. to completely dissolve it;

[0011] (2) filtering the mixture obtained in step (1) while hot, concentrating the filtrate, adding an acidic solution, standing at room temperature for 30-60 minutes, and centrifuging to obtain an insoluble substance in the lower layer;

[0012] (3) The insoluble matter in the lower layer is extracted again through steps (1) and (2) in sequence, and then transferred into a dialysis bag for dialysis for 1-3 days. After the dialysis is completed, it is freeze-dried to obtain keratin.

[0013] As a further improvement, the modified citrate is prepared by reacting xylan with citric acid.

[0014] As a further improvement, the synthesis of the modified citrate comprises the following steps:

[0015] (1) stirring and dissolving xylan in an organic solvent, adding citric acid and a catalyst, and ultrasonically treating at 40-60° C. for 10-30 min;

[0016] (2) The mixture obtained in step (1) is adjusted to a pH of 5-6, then added to ethanol for precipitation, and post-treated to obtain modified citrate.

[0017] As a further improvement, the weight ratio of xylan to citric acid is 1:1-3.

[0018] As a further improvement, in the synthesis step of the modified citrate, the catalyst is 4-dimethylaminopyridine.

[0019] As a further improvement, the modified polylactic acid is prepared by reacting polylactic acid, composite nanomaterials and L-lactide.

[0020] As a further improvement, the synthesis of the modified polylactic acid comprises the following steps:

[0021] (1) preparing a sterile culture medium with peptone, yeast extract, glucose and disodium hydrogen phosphate, adjusting the pH to 6-7 with an acidic solution, then adding agar and xylindoleacetobacter, culturing under constant temperature and humidity conditions for 3-7 days, obtaining a membrane material at the air-liquid interface, washing it with distilled water, freeze-drying it, grinding and sieving it to obtain a composite nanomaterial;

[0022] (2) adding the composite nanomaterial, L-lactide and the catalyst into a flask, adding an organic solvent, heating and stirring for 1-5 hours, and post-treating to obtain a modified grafted product;

[0023] (3) The polylactic acid, the modified grafted product and the organic solvent are stirred and mixed at room temperature, and post-treated to obtain the modified polylactic acid.

[0024] As a further improvement, the amount of the modified graft added is 1-2% of the amount of the polylactic acid added.

[0025] As a further improvement, in the synthesis step of the modified polylactic acid, the catalyst is stannous octoate.

[0026] As a further improvement, the plasticizer is at least one of polyethylene glycol, glycerol, and sorbitol.

[0027] The present invention also provides a method for preparing a bio-environmentally friendly plastic based on cockroach body waste, which is characterized by comprising the following steps:

[0028] (1) dissolving cockroach protein, modified polylactic acid, a plasticizer and a binder in a mixed solution of ethanol and water according to weight, heating and stirring to mix, and obtaining a film-forming solution;

[0029] (2) pouring the film-forming liquid into a mold, cooling, characterizing, and drying, thereby obtaining a bio-environmentally friendly plastic based on cockroach body waste.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention provides a bio-environmentally friendly plastic based on cockroach body waste and a preparation method thereof, so that the prepared bio-environmentally friendly plastic has higher tensile strength and elongation at break, indicating that it has good mechanical properties and is easy to process and shape, and has a higher sample weight loss rate in a shorter period, indicating that the bio-environmentally friendly plastic has good degradation performance, does not generate pollution, and is environmentally friendly. DETAILED DESCRIPTION

[0032] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0033] In the following examples, except keratin, modified citrate, and modified polylactic acid, the other compound monomers and related reagents used can be purchased from the market, wherein peptone was purchased from J&K Technology Co., Ltd. with a product number of 1268734, yeast extract powder was purchased from Beijing Aoboxing Biotechnology Co., Ltd. with a product number of 01-013, glucose was purchased from Tianjin Damao Chemical Reagent Factory with a product number of 3588, agar was purchased from J&K Technology Co., Ltd. with a product number of 010-08725, xyloglucanacetobacter was purchased from Ningbo Mingzhou Biotechnology Co., Ltd. with a product number of BMZ133467, polylactic acid was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. with a product number of P875107, and polyethylene glycol was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. with a product number of P815609.

[0034] The extraction of keratin includes the following steps:

[0035] (1) Clean and crush the cockroach shells, weigh 10 g of the cockroach shell powder, add it to 150 mL of a 5.2% NaOH solution, and stir at 80° C. until it is completely dissolved;

[0036] (2) The mixture obtained in step (1) was filtered while hot, and the filtrate was concentrated and 30 mL of glacial acetic acid was added. After standing for 30 min, the mixture was centrifuged at 8000 rpm to obtain the insoluble matter in the lower layer;

[0037] (3) The insoluble matter in the lower layer is extracted again by repeating steps (1) and (2) in sequence, and then transferred into a dialysis bag for 3 days. After the dialysis is completed, the keratin is freeze-dried at -45°C in vacuum to obtain keratin.

[0038] The synthesis of modified citrate esters comprises the following steps:

[0039] (1) 0.75 g of xylan was dissolved in 20 mL of dimethyl sulfoxide with stirring at 500 rpm for 30 min, and then 2.10 g of citric acid and 0.2 g of 4-dimethylaminopyridine were added and ultrasonically treated at 50 °C for 20 min;

[0040] (2) The pH of the mixture obtained in step (1) was adjusted to 5.5, and then added to 60 mL of ethanol for precipitation for 30 min. The solid was filtered and dried at 60° C. for 60 min to obtain a modified citrate.

[0041] The synthesis of modified polylactic acid comprises the following steps:

[0042] (1) In 1000 mL of ultrapure water, 10.0 g of peptone, 5.0 g of yeast extract, 20.0 g of glucose and 2.0 g of disodium hydrogen phosphate were added in sequence to prepare a sterile culture medium, the pH was adjusted to 6 with glacial acetic acid, and then 10 g of agar and 15 g of xylindoleacetobacter were added, and the culture was carried out at 30° C. and 50% relative humidity for 7 days to obtain a membrane material at the gas-liquid interface, which was cleaned with distilled water, freeze-dried, ground and sieved with a standard sieve with a pore size of 0.45 mm to obtain a composite nanomaterial;

[0043] (2) 0.5 g of the composite nanomaterial, 0.5 g of L-lactide and 0.5 g of stannous octoate were added to a flask, and then 30 mL of dimethyl sulfoxide was added. The mixture was reacted at 80 °C for 1 h, and then the temperature was raised to 140 °C and stirred for 3 h. After the reaction, the mixture was poured into a mixed solution of 50 mL of dichloromethane and 50 mL of ethyl acetate, and the mixture was centrifuged at 8000 rpm to obtain a precipitate. The operation was repeated twice to obtain a modified grafted product.

[0044] (3) 0.2 g of the modified grafted product, 20 g of polylactic acid, and 50 mL of dichloromethane were stirred and mixed at room temperature for 2 h, and then the solvent was removed by rotary evaporation to obtain modified polylactic acid.

[0045] The preparation method of Example 1-4 and Comparative Example 1-2 comprises the following steps:

[0046] (1) Dissolving cockroach protein, modified polylactic acid, a plasticizer and a binder in a mixed solution of 60 mL of ethanol and 100 mL of water according to weight, stirring and mixing at 50° C. for 60 min at a stirring speed of 500 rpm to obtain a film-forming solution;

[0047] (2) pouring the film-forming liquid into a mold, naturally cooling, characterizing, and drying, thereby obtaining a bio-environmentally friendly plastic based on cockroach body waste.

[0048] The components and contents used in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1 below:

[0049] Table 1

[0050]

[0051]

[0052] The tensile strength, elongation at break and biodegradability of the bio-environmentally friendly plastic based on cockroach body waste prepared in Examples 1-4 and Comparative Examples 1-2 were tested as follows:

[0053] Tensile strength: tested according to ASTM D638 standard, tensile speed is 10mm / min;

[0054] Elongation at break: Tested according to ASTM D638 standard;

[0055] Biodegradation performance: According to GB / T 19811-2005 standard test, the disintegration test is carried out by soil burial method, and the test is carried out in flower pot soil. The prepared sample is weighed (W1) and buried 3-5cm from the surface of the pot soil. Water is applied once every 5 days (tap water, pH=6.8, water temperature adjusted to 20℃), and the amount of water is appropriate to be enough to seep a small amount of water at the bottom of the flower pot. Every two weeks or so, take out the buried sample, wash it, dry it and weigh it (W2), and calculate the sample weight loss rate according to the following formula:

[0056] Sample weight loss rate = (W1-W2) / W1×100%.

[0057] The test results are shown in Table 2 and Table 3, as follows:

[0058] Table 2

[0059]

[0060]

[0061] Table 3

[0062]

[0063] It can be seen from Example 2 and Comparative Example 1 in Tables 2 and 3 that, compared with the bio-environmentally friendly plastic prepared using unmodified polylactic acid, the bio-environmentally friendly plastic prepared using modified polylactic acid has higher tensile strength and elongation at break, indicating that the mechanical properties are better, and has a larger sample weight loss rate in a shorter period, indicating that the bio-environmentally friendly plastic has better degradation performance.

[0064] It can be seen from Example 2 and Comparative Example 2 that compared with the bio-environmentally friendly plastic prepared using unmodified citrate as a binder, the bio-environmentally friendly plastic prepared using modified citrate as a binder has higher tensile strength and elongation at break, and can also accelerate degradation to a certain extent, thereby improving biodegradability.

[0065] It can be seen from the test results of Examples 1-4 that the bio-environmentally friendly plastic based on cockroach body waste prepared by the preparation method provided by the present invention has higher tensile strength and elongation at break, indicating that the mechanical properties are excellent and easy to process and shape, and has a higher sample weight loss rate in a shorter period, indicating that the bio-environmentally friendly plastic has good degradation performance, does not cause pollution, and protects the environment and human health.

[0066] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A bio-environmentally friendly plastic based on cockroach waste, characterized in that: The bio-environmentally friendly plastic comprises the following components in parts by weight: 30-50 parts of cockroach body protein, 10-20 parts of modified polylactic acid, 5-15 parts of plasticizer, and 1-5 parts of adhesive; The cockroach body protein is keratin; The adhesive is a modified citrate.

2. The bio-environmentally friendly plastic based on cockroach waste according to claim 1, characterized in that: The extraction of keratin comprises the following steps: (1) cleaning the cockroach shell and crushing it, then placing it in an alkaline solution and stirring it at 50-80° C. to completely dissolve it; (2) filtering the mixture obtained in step (1) while hot, concentrating the filtrate, adding an acidic solution, standing at room temperature for 30-60 minutes, and centrifuging to obtain an insoluble substance in the lower layer; (3) The insoluble matter in the lower layer is extracted again through steps (1) and (2) in sequence, and then transferred into a dialysis bag for dialysis for 1-3 days. After the dialysis is completed, it is freeze-dried to obtain keratin.

3. The bio-environmentally friendly plastic based on cockroach waste according to claim 1, characterized in that: The modified citrate is prepared by reacting xylan with citric acid.

4. The bio-environmentally friendly plastic based on cockroach waste according to claim 1, characterized in that: The synthesis of the modified citrate comprises the following steps: (1) stirring and dissolving xylan in an organic solvent, adding citric acid and a catalyst, and ultrasonically treating at 40-60° C. for 10-30 min; (2) The mixture obtained in step (1) is adjusted to a pH of 5-6, then added to ethanol for precipitation, and post-treated to obtain modified citrate.

5. The bio-environmentally friendly plastic based on cockroach waste according to claim 3 or 4, characterized in that: The weight ratio of the xylan to the citric acid is 1:1-3.

6. The bio-environmentally friendly plastic based on cockroach waste according to claim 1, characterized in that: The modified polylactic acid is prepared by reacting polylactic acid, composite nanomaterials and L-lactide.

7. The bio-environmentally friendly plastic based on cockroach waste according to claim 1, characterized in that: The synthesis of the modified polylactic acid comprises the following steps: (1) preparing a sterile culture medium with peptone, yeast extract, glucose and disodium hydrogen phosphate, adjusting the pH to 6-7 with an acidic solution, then adding agar and xylindoleacetobacter, culturing under constant temperature and humidity conditions for 3-7 days, obtaining a membrane material at the air-liquid interface, washing it with distilled water, freeze-drying it, grinding and sieving it to obtain a composite nanomaterial; (2) adding the composite nanomaterial, L-lactide and the catalyst into a flask, adding an organic solvent, heating and stirring for 1-5 hours, and post-treating to obtain a modified grafted product; (3) The polylactic acid, the modified grafted product and the organic solvent are stirred and mixed at room temperature, and post-treated to obtain the modified polylactic acid.

8. The bio-environmentally friendly plastic based on cockroach waste according to claim 7, characterized in that: The added amount of the modified graft is 1-2% of the added amount of polylactic acid.

9. The bio-environmentally friendly plastic based on cockroach waste according to claim 1, characterized in that: The plasticizer is at least one of polyethylene glycol, glycerol and sorbitol.

10. A method for preparing a bio-environmentally friendly plastic based on cockroach waste according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) dissolving cockroach protein, modified polylactic acid, a plasticizer and a binder in a mixed solution of ethanol and water according to weight, heating and stirring to mix, and obtaining a film-forming solution; (2) pouring the film-forming liquid into a mold, cooling, characterizing, and drying, thereby obtaining a bio-environmentally friendly plastic based on cockroach body waste.

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