Modification Of SBS And Studies Of Anionic Polymerization Of Several Polar Monomers

Based on the general synthesis of SBS by anionic polymerization mechanism, we have carried out the copolymerization of SBS with several polar monomers by conversion of end-group of SBS. Content consists of two aspects chiefly: one is the modification of SBS by co-polymerizations of maleic anhydride, caprolactone, acrylonitrile with it under mild conditions, the other is primary grope to polymerizations of polar monomers initiated by lithium organocuprate. We endeavor to realize the block-copolymerization of non-polar monomers with mass polar monomers by means of the conversion of alkyl lithium and alkoxyl lithium to lithium organocuprate.The polymerization of living SBS, which initiated by n-BuLi, was carried on in cyclohexane and THF as polar additive around 60～80℃ in 2L metal kettle. Then the living SBS solution was translated into flask under nitrogen atmosphere, where after, the carbon-lithium chain ends of SBS were converted to alkoxyl lithium ends by the excessive addition of ethylene oxide to reduce the activity of the chain ends under ambient temperature. The product was obtained through addition of maleic anhydride, caprolactone, acrylonitrile respectively to alkoxyl SBS. The effect of reactive conditions such as temperature, time, concentration, solvent in a feasible range to copolymerization have been researched, and the fitting polymeric conditions have also been conformed.Several products have been characterized by 1HNMR spectra and GPC curve. 1HNMR spectra of purified products indicated that quantitative polar groups was introduced into main chain of SBS.The micro-phase morphology of blends which obtained by means of blending products with PVC at the ratio of 10﹕3, while SBS with PVC were observed by TEM. Observations showed that the compatibility of products with PVC excel that of SBS with PVC, it is obvious that polar group enhance the compatibility of SBS with PVC.furthermore, we researched the thermal-stability of lithium organocuprate initiating polymerization of MMA. some factor such as reaction temperature, preparing method of copper salts and derivation have remarkable effect on the thermal-stability. The result indicated that the higher reaction temperature, the worse thermal-stability of system. The order of lithium organocuprates deriving from different copper salts is CuSCN>CuI>CuBr>CuCl.Corresponding polymers that have broad MWD was obtained through polymerization of acrylonitrile, caprolactone, methyl methacrylate initiated by lithium organocuprate about -10℃ in THF. The effect of several reaction conditions to polymerization of MMA has been researched. It has been proved that the reaction rate is very rapid and yield is high, all of lithium organocuprates having various Li/Cu molar ratio can catalyze polymerization of MMA, as well as the obtained product has higher molecular weight and protean MWD.