Polydicyclopentadiene PDCPD is a homopolymer or copolymer of dicyclopentadiene (DCPD). It is a cross-linked three-dimensional network structure engineering plastic. The density is 1.03g/cm3, and the heat distortion temperature is 120℃. No deformation at -40°C. Resistant to general acids, alkalis and organic solvents, but not resistant to aromatic hydrocarbons and halogenated hydrocarbons. The flexural modulus is 1790～2070MPa. Tensile strength 34MPa. Glass transition temperature 185.5 ℃. The notched impact strength of the cantilever beam is 427J/m. It is prepared by ring-opening disproportionation polymerization of dicyclopentadiene in the presence of a catalyst composed of tungsten hexachloride and diethylaluminum monochloride. Various parts can custom DCPD molding be made by reaction injection molding. Used as auto parts, such as bumpers, bumpers, dashboards, fenders, etc., and also used as sporting goods shells, chemical-resistant containers, etc.
In summary, PDCPD has very superior performance, allowing it to be practically applied in a wide range of fields such as construction machinery, automobiles, military industry, and medical equipment.
PDCPD products are generally produced by RIM process. Based on high-purity DCPD (≥98%), they are obtained by ring-opening shift polymerization (ROMP). The raw materials are mostly two-component systems (A and B liquids). The process for:
(1) Raw materials. Material A and B are low viscosity liquids. Material A contains DCPD, activator and additives, and material B contains DCPD, catalyst and additives. The viscosity is controlled at 0.2~1.0 Pa.s, and the material temperature is 20~30℃;
(2) Mold. The mold needs to be preheated to 40~80℃. When the product is thick or large, the temperature difference between the female mold and the male mold should be 20~40℃;
(3) Measurement, mixing and injection molding. The mass ratio of A and B feed liquid is preferably 1:1, and the difference should be less than 5%;
(4) Decompression and demoulding. When the product structure is simple, it can be self-released, and when there are reinforcing ribs or other complex structures, a release agent can be used;
(5) finishing and modification. The molding cycle of the whole production is about 6min. PDCPD-RIM reaction injection molding equipment
In recent years, environmental factors have caused some developed countries to strictly control the use of FRP products, while PDCPD belongs to "environmentally friendly materials". The standardization of national environmental protection policies, the strengthening of citizens' awareness of environmental protection and the improvement of market awareness have provided an opportunity for the rapid development of PDCPD products.
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