Study on Application of Plant Fiber Polyether Polyols in Countries of the World

“In the past, polyurethane polyols were mainly produced from petrochemical resources, and petrochemical resources could not be regenerated in a short period of time. Now that waste plant materials such as straw and rice straw are used, polyether polyols can also be synthesized, and the production process is safe. 'Three wastes' is produced, the product is stable, and there are bright prospects for polyurethane application.” Polyether polyol technology and products.

According to reports, the current industrial production of traditional polyether polyols generally use pretreatment, polymerization, adsorption and adsorption, filtration, dehydration, distillation and other technological processes, the production process of "three wastes". It is understood that the current advanced production process will produce approximately 30 kilograms of waste liquid per ton of polyether polyol product produced. Although the amount is not large, it must be treated before discharge. In addition, the filtration of polyethers in solid wastes must also be cleaned and recycled with solvents, resulting in higher costs.

Plant fiber polyether polyol is mainly corn, wheat straw and other plants as raw materials, raw materials are readily available. It is understood that China has more than 700 million tons of crop stalks each year, and a large amount of papermaking black liquor, these are very good sources of raw materials for plant polyether polyols.

At present, all countries in the world have increased the application of plant fiber polyether polyols. There are about five types of plant fiber polyether polyol technology at home and abroad, namely high-temperature liquefaction modification technology, medium-low temperature liquefaction technology, selective process liquefaction technology, biological enzymolysis technology, and separation direct application technology. Separation direct application technology has high energy consumption and faces elimination; bioenzymatic technology is not high in energy efficiency, and it is still in the experimental stage; high temperature liquefaction modification technology and selective process liquefaction technology are somewhat less safe; medium and low temperature liquefaction technology is under normal temperature and pressure conditions. Under the synthesis, the production safety is high, the product stability is good, and the yield is high. It is the mainstream technology of domestic synthetic plant fiber polyether polyols. Fudan University, Chinese Academy of Sciences, Dalian University of Technology, and East China University of Technology have all carried out research on plant polyether polyols, but they have only changed in raw materials. The others are not much different.

According to Liu Weifeng, plant fiber polyether polyols can be roughly divided into plant cellulose polyether polyols, lignin polyether polyols, hey fiber polyether polyols, and vegetable tannin polyether polyols, all of which are now in the polyurethane field. The application can be made of rigid foam, soft foam, elastomer, paint, and viscose. At present, the rigid foam application technology is relatively mature, and it has applications in the fields of polyurethane wood, high-strength rigid foam, special packaging, antibacterial products, insulation and construction, and automobiles. Among them, Shanghai Fudan University made use of plant polyurethanes to make floating nets for sea fishing nets and life-saving belts at sea, which have been used in disaster accidents such as tsunami.

Liu Weifeng said that although there are several companies in the country that can mass-produce plant fiber polyether polyol products and have obtained certain applications, there are still problems in large-scale production and marketing. On the one hand, the current domestic production of plant fiber polyether polyol products has a darker color and is not suitable for surface products and has poor market acceptance. On the other hand, large-scale production still requires a large amount of investment, while government support is limited. In addition, propaganda of plant fiber polyether polyols is not enough, and many users do not understand product performance.

Liu Weifeng also believes that future research in this field should focus on the production of plant polyether polyols from agricultural and forestry waste and papermaking black liquor lignin, and further expand the use of plant polyether polyols.