Optimization And Application Of Trans-1,4-Polyisoprene By A Supported Titanium Catalyst System Solution Polymerization

Trans-1,4-polyisoprene(referred to as the TPI) has the identical chemical composition with Natural Rubber(NR),But there is a big difference in the mechanical properties.TPI has three characteristics that contain a double bond structure, molecular chain flexibility and trans structure orderliness. TPI’s double bond suggests it can use sulfur cure systems to form a soft elastomer. At room temperature, it is a kind of plastic with low melting point, which can be made directly on the body shape of complex medical splints, orthopedic equipment and so on. Conventional vulcanizing method of rubber can be used to crosslink. When crosslinking density is is low, it is a kind of material which has temperature shape memory function. The vulcanizate of TPI has the properties of dynamic low heat, excellent flex resistance, low rolling resistance. Given these characteristics of TPI, which can be used as functional materials, shape memory materials, carrier materials of rubber chemicals, and it can also be used in the field of rail transportation vibration and high-speed tires fields.Trans-1,4-polyisoprene(TPI) was synthesized by solution polymerization with the supported titanium catalyst and four different solvent. The important factors in the reaction course were studied in details.In the monomer concentration of 4 mol/L, supported titanium containing catalyst of 5.4%, through a series of experiments to explore the best solvent, Al/Ti (the molar ratio, similarly hereinafter) and Ti/IP (the molar ratio, similarly hereinafter). The trans structure content was higher than 98% as checked by FTIR and NMR.Determing the melting point and crystallinity by DSC test.The intrinsic viscosity and GPC measurement to obtain viscosity-average molecular weight, the number-average molecular weight and molecular weight distribution. The mechanical properties of pure TPI, vulcanized TPI and TPI/NR were measured and studied the impacted of TPI on the mechanical properties of NR.Many metal elements were existing in the trans-1,4-polyisoprene(TPI), synthesized by the solution polymerization. Some methods were put forward to decreasing the content of residue single metal elements. The first attempt was to pure the TPI with toluene for 3 days in Soxhlet extractor. Plasma atomic emission spectroscopy (ICP) test showed that the content of the residual single metal elements were decreased, but still high. Then use the modified scheme:dissolved TPI in toluene with the constant temperature, rotary steam, added hydrochloric acid, static crystal in ice salt, high-speed stirring, ethanol precipitation and finally obtained the purified TPI. After vacuum drying, ICP test showed that the content of the residual single metal elements were decreased significantly, there were about in 300-500 ppm. FTIR and NMR test showed that the purified product was still trans-1,4-polyisoprene, its trans structure content was 98.20%.