Polymerization Of Conjugated Diene And Characterization Of Copolymer

The copolymerizations of conjugated diene,ethylene and styrene derivates monomers with high regio-and stereoselectivities,offering highly organized and sequence-controlled polymers are the most challenging goals in the polymer science.Thus,the theme focus on the synthesis of new rubber materials through the copolymerization of ethylene,conjugated diene,functional conjugated diene,styrene and polar styrene derivates by employing rare-earth complexes.Details are listed as following:(1)The controlled random copolymerizations of ethylene and myrcene have been achieved catalyzed by five Sc complexes varied in steric hindrance and electronic effects.Under the condition of 4 bar ethylene and 60?,fluorene methyridine scandium catalyst displayed the highest catalytic activity.The copolymerization behaviors of ethylene and myrcene were studied under various conditions to screen the most optimized one.Meanwhile,the large scale synthesis of the copolymer was realized as well.Then,the copolymer was mixed with carbon black,sulfur,sulfurizing accelerator and other auxiliaries to characterize the physical and mechanical properties of the sample.(2)The ternary copolymerization of ethylene with styrene and isoprene was implemented by two limited geometrical catalysts.It was found that when the molar amounts of styrene and isoprene were equivalent,the polymerization activity was much lower than that when the molar amounts were drastically divergent.The terpolymers with different contents of styrene and isoprene were prepared by methyl carbine fluorenyl rare-earth scandium catalyst.The copolymers were mixed with carbon black,sulfur,sulfurization accelerator and other auxiliaries to test physical and mechanical properties.(3)A diene monomer with silyl ether protecting group was synthesized from isoprene.The(Flu-CH₂-Py)Y(CH₂Si Me₃)₂(THF)catalyst for homopolymerization of the diene monomer afforded primarily the 3,4-polymerization product with high activity.Then the copolymerization was also performed with isoprene to access different composition copolymers via shifting the feed ratio.The monomer3,4-dimethoxystyrene was synthesized from veratrol.And the polymerization of this monomer was catalyzed by using lithiumbutyl as initiator with 97%conversion.This monomer,afterwards,was able to copolymerize with isoprene and myrcene catalyzed by nBuLi to generate the corresponding copolymers.