The Research For The Synthesis And Properties Of Room Temperature Curing Novel Polyurethane Elastomer

Polyurethane elastomer(PUE), also known as polyurethane rubber, is one species of high molecular synthetic material whose performance is between plastic and rubber, which contains many carbamate groups in the main chain. The superior performance of PUE is given by the unique microphase separation tructure, so it is widely used in national defense and national economy in all areas.Polyurethane elastomer is general synthesized by the oligomer polyols constituting soft segment of the polymer diisocyanate and extender chain agent composing hard segment in the way of step-growth addition polymerization. The average functionality of used oligomer polyols is relatively low. The relative molecular mass is400～6000. Which commonly used are polyether polyol、 polyester polyol、polybutadiene polyol and so on. The soft segment of PUE constituted by polyether polyol is provided with corrosion resistance、hydrolysis resistance、flexing resistance and good caking property. At present the synthesis of polyether polyol is mainly the traditional alkali catalyst process and DMC catalyst process, their raw material basic come from expensive nonrenewable resources oil. If petrochemical products is replaced by a certain amount of renewable resources in production of polyether polyol,it will be the great significance to the future development of PUE and deal with increasingly focus on the energy crisis. For this purpose, many of scientific and technical workers have made great efforts. CPUE products are usually prepared through the high temperature mold pressing formation, but this method would be difficult to realize for some complex shape products or in the environment unable to provide heating or pressure. Therefore, it is necessary to research and explore the PUE cured at room temperature with excellent performance, at the same time it also can save cost and reduce the energy consumption.This topic prepare a series of casting polyurethane elastomers(CPUE) using the quasi-prepolymer system and curing at room temperature. Polyether polyol in the group A uses the renewable caster oil as the initiating agent made from propylene oxide to ring-opening polymerization, and in-depth analysis of its relevance. The infrared spectra is used for the new polyurethane elastomers and the results indicate that the molecular structure contain the characteristic absorption peaks of urethane groups、ether bonds and benzene ring groups. It shows that the experiments have successfully prepared the polyether-based polyurethane elastomers. Through mechanical properties tests, the various influence factors of the mechanical properties of polyurethane elastomers are analyzed in detail. Mechanics performance tests include hardness、rebound resilience、elongation at break、tensile strength、tear strength and so on. The structure of polyurethane elastomers affects their performance, the types of polyether polyols、chain extension agent、-NCO mass fraction、the amount of plasticizer and filler, as well as the NCO index change will lead to the difference of elastomers. Through analysing and discussing informed that these disparities exist certain regularity. The differential scanning caborimetry(DSC) studies show that the flexibility of molecular chain of polyurethane elastomers descend with the content of the hard segment in molecular chain rise, which lead to the glass transition temperature(Tg) rise. Because of the polyols used are polyether polyol, which the cohesive energy of ether linkage is lower, the polyurethane elastomers prepared all have better resistance to low temperature. The performance of resistance to high temperature is studied by the Thermo gravimetric Analyzer(TG).The results show that the hard segment content and type of chain extension agent will affect the thermal stability of PUE. The scanning electron microscopy(SEM) studies observe that the polyurethane elastomers prepared in the experiments exist obvious microphase separation structure and the dispersibility of the packing particles is not good enough in the elastomer, existing agglomerate phenomenon.