Corn plastic -- the terminator of white pollution
polylactic acid, a biopolymer material developed by Professor Ren Jie, deputy dean of the school of materials and science and engineering of Tongji University, recently won an innovation award at the Industrial Expo. This kind of polylactic acid, commonly known as "corn plastic", is considered to be the terminator of "white pollution" brought by traditional chemical plasticsProfessor Ren Jie told that the raw material of polylactic acid is not only corn, but also additives in waste plastics. Many other crops can be used to extract lactic acid. Therefore, it is more appropriate to call polylactic acid "biomass plastic"
bioplastics have good prospects, high prices and difficult to promote.
today, with the depletion of petroleum, coal and other fossil resources, the development and application of biological resources have been concerned by scientists around the world, and also led to the vigorous development of the biomass industry. This emerging industry uses renewable or recycled organic substances such as crops and livestock manure as raw materials to produce fuel, energy and biomass materials (including plastics, fibers, etc.) through biochemical methods
Professor Ren Jie's research is aimed at polylactic acid, one of the most important biomass materials. This is a high molecular compound polymerized by lactic acid, which has the same physical properties as modern chemical plastics, and even has some advantages in some aspects. More importantly, polylactic acid can be decomposed by microorganisms in nature and eventually become carbon dioxide and water, which does not pollute the environment. It can also be used as organic fertilizer to be applied to farmland as plant nutrients. The products made of polyethylene, polypropylene and other chemical plastics, even if buried deep underground, will not be decomposed for a long time, resulting in what is often called "white pollution". Therefore, polylactic acid is one of the most likely biomass materials to replace chemical plastics
according to Professor Ren Jie, at present, only one company in the United States can produce polylactic acid on a large scale. The production process of the company adopts the "two-step method", and the production cost is high, and the price per ton is about 3000 US dollars. Although the price is high, it cannot stop the demand of the market, especially in developed countries, which spend a lot of money on promotion. At the Aichi Expo in Japan, polylactic acid was used as the material for everything from tea cups to walls
in China, such a high price is obviously unacceptable to the market. How to reduce the production cost through technical improvement, so as to produce cheap and good polylactic acid has become the focus of Professor Ren's research. At the same time, this topic has also been listed as one of the first 29 industrialization projects of "revitalizing the city through science and education" in Shanghai
current results of industrial application of low price and good quality made in China
after 8 years of research and 1 year of production, but after industrialization and amplification on a fixture for some new materials and special materials, Professor Ren Jie led the scientific researchers to finally develop an advanced process of "one-step" extraction of polylactide "nonmetallic tension, pressure and universal material testing machine" verification regulation, which is mainly aimed at small load testing machine (mechanical sinusoidal pendulum testing machine has been gradually eliminated by electronic testing machine) acid. Through the organic combination of bioengineering technology and polymer synthesis technology, "one-step" can synthesize lactic acid extracted from corn into polylactic acid particles, which greatly reduces the production cost. The ex factory price is about 10000 yuan per ton, which is close to the current price of chemical plastic particles. Therefore, PLA has the conditions for popularization, application and industrialization in ChinaThe significance of polylactic acid application in China is not only reflected in environmental protection, but also will play a positive role in the construction of circular economy and energy-saving society. The raw materials of chemical plastics are extracted from the non renewable fossil resource petroleum, which is becoming a scarce and consumable resource. Polylactic acid extracted from plants obviously has an inexhaustible supply of raw materials, and the decomposed polylactic acid will be absorbed by plants to form a material recycling. And compared with chemical plastics, polylactic acid will not produce more carbon dioxide. Because corn, the raw material of polylactic acid, will consume carbon dioxide through plant photosynthesis during its growth. In addition, the industrialization of polylactic acid will greatly improve the added value of crops. Taking corn as an example, China's annual inventory reaches more than 30 million tons, and most of it is used as feed. If it is used to produce polylactic acid and form an industrial chain of "corn lactic acid polylactic acid copolymer blends various applied products", it can greatly increase the price of corn and farmers' income
at present, Professor Ren Jie has applied for a number of patents at home and abroad, forming a patent group for the preparation and application of polylactic acid with independent intellectual property rights. Tongji University, Shanghai Venture Capital Co., Ltd., Shanghai Xinli Industrial Microbiology Technology Co., Ltd. and Shanghai Yangpu Technology Investment Co., Ltd. have established Shanghai tongjieliang biomaterials Co., Ltd. At present, customers with a demand of tens of thousands of tons have come to the door, which shows the popularity of the project
in addition to building an independent intellectual property rights and technical standard system of environmental protection and high-performance surface materials, polylactic acid can be used in engineering materials, packaging materials, household appliances, agricultural mulching film, etc., and it is also very useful in the field of medicine and medical treatment. Bone nails and surgical sutures made of polylactic acid can be completely degraded in the body, and there is no need to perform medical procedures such as extraction and suture removal. Polylactic acid can also produce tissue engineering scaffolds for human bone and artificial skin, on which bone cells or skin cells are cultured. When the scaffold material is degraded, the artificial bone and artificial skin also grow. The slow-release capsule carrier made of polylactic acid can be gradually digested and degraded in the human body, and the drug can be continuously released within a certain period of time
source: Shanghai Science Popularization