Problems existing in the hottest degradable plasti

Problems of degradable plastics

degradable plastics, as a new technical way to treat plastic waste, has made satisfactory progress after years of research and development. Of course, the torque of the light engine refers to the torque output from the crankshaft end of the engine. Although the processing of light biodegradable plastic products is simple and the cost is low, it is difficult to control the degradation in time, so it is not suitable to enter the landfill system; The degradable plastic filled with starch is difficult to process and its performance is not ideal; Fully biodegradable plastic has ideal degradation performance, but it is difficult to process, expensive, and sometimes controlled degradation, which requires comprehensive composting after use; In addition, the more reasonable technological formula of degradable plastics and the recycling of leftover materials need to be further improved and perfected. Although there are still many problems in the degradation of polymer materials, due to the progress of degradation technology, the relevant problems covering an area of about 200 mu are gradually being solved, and the market prospect is also getting better and better. In order to make the technology of degradable plastics have greater development on the basis of great achievements, from the perspective of development trend, the following aspects are worthy of in-depth discussion and research in the future

1. Study on the practicability of degradable plastics such as disposable mulching film, packaging materials and tableware

degradable plastic products such as disposable mulching film, packaging materials and tableware can be studied through the comprehensive degradation technology of controllable photo oxygen biodegradable plastics filled with edible starch or inorganic minerals. The area of plastic film that can be covered in China is more than 500 million mu, and the dosage is as high as 400000 tons. It is more suitable to use the low-cost photo oxygen biodegradable plastic film. The degradable plastic film with a thickness of 0.005mm-0.015

mm can also use the pure photo oxygen degradation technology of plastic, but it must be time-controlled degradation. For example, the Ministry of agriculture and the light industry association of China will take the lead in formulating national or industrial technical standards for degradable mulching film and organizing the promotion in a planned way, which is of far-reaching significance to solve the problem of farmland pollution by waste mulching film and benefit future generations. For degradable plastic products such as shopping bags, food, sundry packaging bag materials and tableware, their degradation characteristics must meet HJBZ

"technical requirements for environmental labeling products of packaging products", qb/t "degradable polyethylene film for packaging", GB

18006 "General technical conditions for disposable degradable tableware", HBC

"technical requirements for environmental labeling products of disposable tableware". Moreover, it should be emphasized that it should not be discarded at will, and it should also be forcibly recycled, regenerated or incinerated to recover energy

2. Research on fully biodegradable plastics is an important development trend of degradable plastics at present.

from the perspective of protecting the ecological balance, research on fully biodegradable plastics is imminent, especially the fully biodegradable plastics with simple synthesis method, reasonable processing process and low cost is an important research topic of degradable plastics at present. Non recyclable medical plastic products such as stitches, stitches, syringes, infusion bags, garbage bags, compost bags, pesticide bottles, cosmetic containers, diapers, women's sanitary napkins and other disposable plastic products should use low-cost fully biodegradable technology. For garbage bags, compost bags, fertilizer bags and other products, high-quality and cheaper fully biodegradable plastics filled with edible starch or inorganic minerals can be studied to meet the needs of the market

3. Use natural recyclable degradable materials as much as possible

according to the latest research report of the International Association of biodegradable polymers (IBAW), the global use of biodegradable plastics doubled between 2001 and 2003, and the total use has risen to 40000 tons/year. IBAW said that although this figure also includes biodegradable materials with oil as raw materials, oil resources are becoming increasingly scarce. As long as the technology permits, producers will use natural recyclable degradable materials as much as possible. At present, biodegradable plastics made from starch and vegetable oil have occupied a dominant position in the market. Recent surveys in several countries have shown that consumers are very interested in this kind of packaging material. What is more interesting is that consumers are willing to pay more for it. Recently, a survey conducted by grapentine, an American market research institution, found that 41% of American consumers and 59% of European consumers are very eager to buy biodegradable plastics made of natural materials, which have made significant progress in the original products and re packaged food through type evaluation. About 77% of European consumers are willing to pay 5 euro cents more for this, while 74% of American consumers are willing to pay 10 cents more. IBAW predicts that the share of natural biodegradable plastics in the biodegradable plastics market will continue to rise, especially in the current situation of high oil prices

4. Thermoplastic starch resin is one of the most promising fully biodegradable plastics at present.

it deforms and disorder the starch molecules to form a thermoplastic starch resin, and then adds a very small amount of plasticizers and other additives, which is the so-called all starch plastic. Among them, the starch content is more than 90%, and a small amount of other substances added are also non-toxic and can be completely degraded, so full starch is a truly fully degradable plastic. Almost all plastic processing methods can be applied to the processing of all starch plastics. All starch plastic is considered as the most promising fully biodegradable plastic at home and abroad. Sumitomo Corporation of Japan, wanler

Lambert Corporation of the United States and ferrazzi Corporation of Italy claim to have successfully developed all starch plastics with a starch mass fraction of 90% - 100%. The products can be completely biodegradable within one year without leaving any traces and pollution, and can be used to manufacture all kinds of containers, films and garbage bags. Germany Battelle Research Institute developed degradable plastics from improved green pea starch with high amylose content, which can be processed and molded by traditional methods. As a substitute for PVC, it can be completely degraded in humid natural environment

5. Carbon dioxide based biodegradable plastic is a research project with broad development prospects at present.

auspicious equality in Inoue, Japan, found that carbon dioxide can be polymerized with epoxide to form aliphatic polycarbonate (APC), which is the most promising carbon dioxide copolymer so far. Takanashi et al. Used the terpolymer of carbon dioxide, propylene oxide and epoxide containing ester bond as drug sustained release agent. Masahiro et al. Prepared PPC microspheres by evaporating solvent as the carrier of drug release system, and studied the factors affecting the drug release rate of the system, such as the molecular weight of PPC, drug content, etc. The results showed that the drug release rate increased with the decrease of the diameter of the microspheres or the increase of the loaded drug concentration, but the drug release rate and biodegradability had nothing to do with the molecular weight of the copolymer. The morphology of the microspheres before and after drug release was observed by SEM, which confirmed that PPC microspheres supported the long-term and uniform release of drugs. American experts used a new technology, using a special zinc catalyst, to mix and copolymerize carbon dioxide and ethylene oxide (or propylene oxide) in a certain proportion, and then made plastic packaging materials with new characteristics. The carbon dioxide based fully biodegradable plastic project implemented by China Jiyou group and Changchun Institute of Applied Chemistry, Chinese Academy of Sciences has been listed in the National 863 scientific research plan. It is a research and development project of new high-tech environmental protection materials with broad development prospects

6. Research on the definition and evaluation methods of degradable plastics is the basis for the promotion of degradable plastics

but developed countries in the world, especially the United States, have also done a lot of research in this regard. At present, American ASTM has published the following test standards: relevant evaluation test standards for biodegradable plastics, astmd, astmd, ASTM

D, astmd. Relevant evaluation and test standards for photodegradable plastics, astmd, astmd, ASTM

D. Environmental safety related evaluation test standard, astmd. At present, the relevant test standards published in China are as follows: gb18006

"general technical conditions for disposable degradable tableware", gb/t18006 "Test method for degradation performance of disposable degradable tableware", HJBZ

"technical requirements for environmental labeling products of packaging products", HBC "statistical data of technical requirements for environmental labeling products of disposable tableware", qb/t

"degradable polyethylene film for packaging". In the future, it is still necessary to refer to the relevant test standards of developed countries and China, and in combination with the market promotion of all kinds of degradable plastics products, in-depth research on the definition and evaluation methods of degradable plastics, and constantly improve and perfect the relevant test standards, which is the basis of the promotion of degradable plastics products and the premise of industrialization