含有联苯侧基聚乙炔的合成及其气体渗透性能

合成了含有取代联苯及烷基硅取代基的二芳基乙炔单体（1a~1d），以TaCl5-n-Bu4Sn作催化剂聚合得到聚合物2a、2b和2d。 所得聚合物在常规有机溶剂中具有良好的溶解性。 用聚合物2a和2b的甲苯溶液浇铸制备了均质膜。 采用三氟乙酸对聚合物2a和2b膜进行去硅化反应，制备了不溶性膜3a和3b。 热重分析表明,所得聚合物均具有高的热稳定性，在空气中的热失重起始温度分别为340和430 ℃。 聚合物2a和2b的氧气渗透系数（PO2)分别为260和390 barrers，去硅化膜3a和3b的PO2分别下降至73和180 barrers。 聚合物膜的O2/N2分离系数为2.4~3.3，并随PO2的增加而减小。 由气体在聚合物膜中的扩散系数和溶解系数的测定，扩散系数的降低是导致去硅化膜气体渗透系数下降的主要原因。

Synthesis and Gas Permeation Properties of Polyacetylenes Containing Biphenyl Pendent Groups

Diarylacetylene monomers(1a~1d) containing substituted biphenyl and Si groups were synthesized and then polymerized with TaCl5-n-Bu4Sn catalyst to generate the corresponding polymers(2a,2b,and 2d).The produced polymers showed good solubility in common organic solvents.Polymers 2a and 2b afforded free standing membranes by casting from their toluene solution.Desilylation of membranes 2a and 2b was carried out with trifluoroacetic acid to give membranes 3a and 3b,which were insoluble in any organic solvents.According to thermogravimetric analysis,both the trimethylsilyl-containing and the desilylated polymers exhibited high thermal stability,the onset temperatures of mass loss in air were 340 ℃ and 430 ℃,respectively.The oxygen permeability coefficients(PO2) of polymers 2a and 2b were 99 and 160 barrers,respectively.Upon desilylation,the PO2 of 3a and 3b decreased to 22 and 65 barrers,respectively.The separation factors of oxygen against nitrogen(PO2/PN2) of the present polymer membranes ranged from 2.4~3.3,and they tend to decrease as the PO2 increased.By determining the gas diffusion coefficient(D) and gas solubility coefficient(S),the result indicates that the decrease of gas permeability upon desilylation was mainly derived from the decrease of D value.