聚苯醚的溴化及其对富氧性能的影响

利用亲电反应及自由基反应分别对聚苯醚进行了不同程度的溴化。测定了不同温度下对O_2和N_2的透过率及相应的玻璃化转变温度和密度。发现苯环上的溴化有利于提高O_2和N_2的透过率,而选择性基本不变。甲基上的溴化大大提高了O_2、N_2的选择性,但透过率下降较多。苯环上溴含量与Tg呈很好的线性关系,密度亦随溴含量的增加而增加。透过率与温度的关系符合Arrhenius方程。溴化后的聚苯醚其透过活化能略有下降,并计算了溴化聚苯醚的摩尔自由体积和摩尔内聚能,发现其比值越大,O_2、N_2的透过率越大。

Bromination of Poly (2,6-Dimethyl-1,4-Phenylene Oxide) and Their Oxygen Enrichment Behavior

Aryl-and benzyl-brominated PPO were prepared by electrophilic and rad-ical reactions respectively, their structure were characterized by ~1H NMR andDSC. Tg increased lineariy with the percentage of aryl-bromine, but decreasedwith the extent of benzyl bromination. Permeability data for O_2and N_2were ob-tained by pressure method at differeat temperatures. The permeabilities of PPOto O_2and N_2were found to be increased with the extent of bromination onphenyl ring while the selctivities for O_2over N_2were hardly changed. In contrast,bromination on methyl group decreased the permeabilities and increased theselectivities largely. By controlling the ratio of bromine on methyl group to thaton phenyl ring, a polymer with both high permeability and high selectivitycould be obtained. These observations were interpreted in terms of change inratio of molar free volume to molar cohesive energy of the polymer series varipermeabilities at various temperatures follow Arrhenius eguation. Permeationactivity energies decreaed with incratures bromine content on phenyl ring.