Polymerization Of Butadiene/Isoprene/Styrene Based On The System Of Functionalized Multilithium Initiator

The functionalized multilithium initiator was prepared from commercial DVB and LHMI in proper temperature, which was reacted in cyclohexane solvent with isoprene for improving solubility and THF as polar additive for improving reaction speed. Polymer prepared by the novel functionalized multilithium initiator could exhibit improved characteristics such as reduced hysteresis loss characteristics and good processiblity. The functionalized multilithium has the advantage of good solubility in nonpolar solvent, fast initiation speed, single solvent system, simplified preparation technology, short synthesis time and low cost. The present thesis utilized the monomers of butadiene, isoprene and styrene to synthesize a series of novel polymers with prepared functionalized multilithium. Following were the typical star-shaped polymers as prepared, including polybutadiene, polyisoprene, copolymer of butadiene/styrene. Furthermore, this thesis also studied systematically the kinetic behavior and heat effect in the polymerization process. The microstructure, molecular weight and its distribution as well as the mechanical properties of the polymers mentioned above were also investigated in detail. From the summary of the full thesis, it came to the conclusions that:1. The functionalized multilithium initiator which featured of cheaper and easily available raw stuff and simple preparation technology was prepared. A series of novel polymers with the prepared functionalized multilithium as initiator, including polybutadiene, polyisoprene, copolymer of butadiene/styrene were synthesized. The results showed that the functionalized multilithium initiator could be used to realize the design for molecular weight of the polymers and get the molecular weight in dispersed distribution.2. The star-shaped polybutadiene and polyisoprene were successfully prepared with functionalized multilithium as initiator and the microstructure of them was investigated in detail under different polar additives dosage and the glass transition temperatures were obtained. The molecular weight and distribution of the two polymers were studied and analysed the influence on MWD of the DVB and TMEDA dosage. 3. The kinetic behaviors in the process of polybutadiene at different initiation temperature, different initiation concentration and different polar additives dosage were studied. And the pseudo first order values of propagation rate kp" under different conditions, the apparent activation energies under different DVB dosage, the apparent values of propagation rate k_p' and the polymerization rate equation were obtained.4. The copolymerization of butadiene/styrene with functionalized multilithium as initiator was studied systematically. The microstructure, glass transition temperature, molecular weight and distribution, dynamic mechanical behaviour were also investigated in detail. It came to the conclusions that the novel SSBR initiated by the functionalized multilithium could exhibit both good wet skid resistance and low rolling resistance.