Study On Polymerizations Of Vinyl Monomers Containing Silicon Atoms And Its Membrane Performance

In this paper, the gas separation membrane that was provided with high permeability andhigh selectivity,was prepared by methacryloyloxy-[ethoxy] trimethylsilane firstly.In thecourse of the study,the homopolymer of methacryloyloxy-[ethoxy] trimethylsilane and thecopolymers of methacryloyloxy-[ethoxy] trimethylsilane and acrylonitrile were prepared bybulk polymerization,and were made into gas separation membrane, respectively. Meanwhile,this study explored the reaction conditions of homopolymers and copolymers impact on theaverage molecular weight and the conversion rate. The structure of homopolymers andcopolymers membranes were analyzed by infrared spectrometer and X-ray diffractometer.The glass transition temerature and mechanical strength of separation membranes weredetected. It was investigated that ratio of the monomers, the amount of the initiator, thereaction temperature and time impacted on the gas permeability of carbon dioxide andnitrogen.The homopolymers of methacryloyloxy-[ethoxy] trimethylsilane study showed that theoptimum reaction conditions were as follows: the reaction of temperature and time wereabout50℃and5h, respectively,and the addition of AIBN was1.5%.At23℃，0.1MPa, theCO2/N2selectivity factor10.6and CO2permeability coefficient were and473.2Barrers,respectively. The main structure of homopolymers was amorphous,in addition,thehomopolymers were dissolved by acetone, THF, DMSO and chloroform,but thehomopolymers was not soluble in ethyl acetate and diethyl ether.The copolymers of methacryloyloxy-[ethoxy] trimethylsilane and acrylonitrile resultedthat the optimum reaction conditions were as follows: the best ratio of monomer was5:5,inaddition, the reaction of temperature and time were about50℃and5.5h, respectively,andthe addition of AIBN was1.5%. At23℃，0.1MPa, the CO2/N2selectivity factor was25.9and CO2permeability coefficient was175.6Barrers. The main structure of copolymers wereamorphous,furthermore,the copolymers were solubled in THF, DMSO and chloroformeasily,however,the copolymers were not dissolved by acetone, ethyl acetate and diethyl ether.It was showed that both the homopolymers membrane and copolymers membrane werenon-porous membrane. At the same time,the glass transition temperature of homopolymersand copolymers were46℃and51℃, respectively.The tensile strength and elongation ofcopolymers were stronger than homopolymers’ obviously,therefore, The mechanical strengthof silicone gas separation membranes were improved. It was important that the CO2/N2selectivity factor of copolymers was better than homopolymers.In short, the desired objectives were achieved.