This project belongs to the technical field of special rubber preparation and involves a new preparation method of high-performance block neofluorosilicone rubber.
Fluorosilicone rubber is a polymer with-Si-O-as the main chain, side chain methyl groups replaced by fluorine-containing groups, and containing a small amount of vinyl siloxane chain ends. It not only maintains the advantages of silicone materials in high and low temperatures, ozone aging resistance, electrical insulation, hydrophobic, flame retardant, non-toxic and non-corrosive, physiological inertness, low surface tension and excellent physical properties, but also has special properties such as oil resistance, solvent resistance and chemical resistance. It is currently the only elastomer that can be used in fuel media at-68 to 230 degrees. It is mainly used for various seals, diaphragms, hoses, etc., and can also be used as wire skins, anti-corrosion liners, anti-fouling insulators for high-speed rail, etc. Due to its widespread application and irreplaceability in the fields of aviation, automobiles, petroleum, chemicals and military industries, high-performance fluorosilicone rubber is a type of special rubber that my country urgently needs to develop.
Focusing on the reactive extrusion polymerization technology of high-performance block fluorosilicone polymers, this project studied the anionic bulk ring-opening polymerization of trifluoropropylmethyl cyclotrisiloxane (D3F). Mainly include:
(1)Invented a new technology for reactive extrusion synthesis of fluorosilicone polymers, solved the mass and heat transfer problems of traditional high molecular weight fluorosilicone polymers in the kettle production process, and was a revolutionary breakthrough in fluorosilicone rubber synthesis technology. The developed fluorosilicone rubber raw rubber has the advantages of high molecular weight, narrow molecular weight distribution, and controllable molecular structure.
(2)A self-made microfluidic tubular reaction device was used to study the kinetics of anionic bulk ring-opening polymerization, which enabled the research on anionic polymerization kinetics to transcend the category of dilute anionic solutions and low conversions, and enter the field of bulk polymerization that was considered a forbidden area in the past., is a breakthrough attempt in polymerization technology.
(3)By using a specific combination system of initiator and accelerator, giving full play to the advantages of the extruder in material shearing and mixing, and adding terminator in time, the "bite back" reaction after fluorosiloxane polymerization can be successfully suppressed. The conversion rate of the product exceeds 95%, which is a significant improvement compared with 85% of traditional kettle polymerization technology.
(4) Preparation of high-performance block fluorosilicone polymers by adding different monomers and functional additives in stages to achieve designability and controllability of molecular weight and molecular structure, which is difficult to achieve by current kettle polymerization technology. The rubber compound obtained on this basis has excellent mechanical properties, oil resistance and heat resistance.
The research and development of this technology has been supported by key projects of the National Natural Science Foundation of China, and has made important breakthroughs in theoretical research and industrialization of anionic polymerization. It has published 6 academic papers and obtained 2 domestic invention patent authorizations, one of which also applied for an international PCT patent.
On the basis of successful pilot tests, we cooperated with Jiangsu Jurong Fuser Company to build a production line with an annual output of 250 to 270 tons in 2011, and at the same time can produce fluorosilicone resins, silicone resins and their block copolymers. and experimental centers have achieved the goal of industrialization. It can continuously and stably produce homopolymeric and block fluorosilicone raw rubber and its blends with high molecular weight (400,000 to 1.8 million) and narrow distribution (distribution coefficient 1.4-1.8), and has developed a series of fluorosilicone rubber compounds such as high tear resistance and high heat resistance, filling domestic gaps and product quality reaching the international advanced level. In the past three years, a total of 94.5 tons of fluorosilicone rubber have been produced and sold, with an added output value of 47.25 million yuan, an added profit of nearly 19 million yuan, and an added tax revenue of 2.835 million yuan.
The research and application of results on this topic will break the situation of my country's dependence on imports of high-performance fluorosilicone rubber raw materials, drive the development and upgrading of related industries, and have huge economic and social benefits.