Study Of Neodymium-based Styrene/lsoprene/Butadiene Polymers

Neodymium-based catalytic system was a type of high-active rare-earth co-catalysts with reasonable prices which can be applied in the synthesis of poly(conjugated olefin)s to obtain high stereoselective (co) polymers. However, there were not various types of poly(conjugated olefin)s obtained with neodymium-based catalytic system, especially the random terpolymers of styrene, isoprene and butadiene with high cis-1,4polyconjugated diene segments and functionalized high cis-1,4poly(conjugated diene)s. In this thesis, based on the three key monomers, butadiene, isoprene and styrene, the synthesis of poly(conjugated olefin)s and their functionalization with neodymium-based catalytic system were studied. Based on these results, we applied two patents in China (CN201210251817.7and CN201310473673.4), one was about the synthesis method of terpolymers consisting of styrene,isoprene and butadiene with high cis-1,4poly (conjugated diene)s segments while the other was about the synthesis method of functionlized poly poly (conjugated olefins)s.The main research topics and key results are as follows:1. The homopolymerization of conjugated dienes was studied with neodymium chloride complexes/methyaluminoxane (NdCl3·nTBP/MAO) and neodymium bis(2-ethylhexyl)phosphate/hydro di-isobutyl-aluminum/chloroform [Nd(P204)3/DIBAH/CHCl3] catalytic system, respectively. It was illustrated that with Nd(P204)3/DIBAH/CHCl3catalytic system, the amount of Al agent was more precise, the polymerization conversions were totally100%and the average molecular weight of the polymers could be designed. Thus, we chose Nd(P204)3/DIBAH/CHCl3catalystic sytem to study the terpolymerizaion and functionalization.2. The terpolymerization of styrene, isoprene and butadiene was studied with Nd(P204)3/DIBAH/CHCl3. The effects of amount of catalyst, polymerizing conditions and monomer ratios on the terpolymerization were investigated. Also the effect of neodymium compounds, aluminum compounds, and the chloride agents on the behaviors of terpolymerization and microstructures of terpolymers were discussed. It was shown that with this kind of catalytic system the terpolymerization could be performed with little amount of aluminum and the terpolymers could be obtained. Also, the microstructures of the terpolymers were high cis-1,4, both the cis-1,4content of polyisoprene and polybutadiene segments were80%. The variation of the ratios of catalytic system did little effect on the microstructure of polyconjugated olefins, especially the1,4-selectivity. With the variation of the ratios of monomer addition, a series of terpolymers with different compositions could be designed:the content of styrene, isoprene and butadiene could be varied in2-15%,30-56%and28-57%.3. The synthetic methods of functionalized polyconjugated olefins with4-vinylpyridine (4Vp) were investigated with Nd(P204)3/DIBAH/CHCl3. The effects of ratio of monomers, amount of catalyst on the synthesis of functionalized polyconjugated olefins were discussed. It was shown that two kinds of functionalized polyconjugated olefins were successfully prepared, functionalized polyisoprene with4-vinylpyridine (NPIp) and functionalized polybutadiene with4-vinylpyridine (NPBd). It was illustrated that both the contents of4Vp in the NPIp and NPBd could be varied from2-19%. Also the cis-1,4content in the NPIp and NPBd were both over95%. We combined the NPIp with azobenzene bearing carboxyl group through hydrogen bond to form azobenzene-NPIp complexes. In addition, the NPIp was also combined with zinc porphyrin complex through coordinated bond to form zinc porphyrin-NPIp complexes.