低温溶液缩聚法合成聚间苯二甲酰对苯二胺及其表征

Synthesis and characterization of poly(p-phenylene isophthalamide) by low temperature solution polycondensation

采用有机硅保护剂三甲基氯硅烷(TMCS)与对苯二胺(PPD)反应生成一种稳定的二胺单体N,N′-双(三甲基硅烷)对苯二胺(BTMSP),再与间苯二甲酰氯(IPC)通过低温溶液缩聚法合成聚间苯二甲酰对苯二胺(PPIA),对PPIA的结构与性能进行了表征。结果表明:采用TMCS保护PPD的方法具有高度可行性;相比于未用保护剂,BTMSP与IPC聚合反应时间缩短,反应3 h后所得PPIA的比浓对数黏度达1.35 dL/g;采用BTMSP合成的聚合物符合PPIA的基本结构,TMCS未参与聚合物的构成;制得的PPIA数均相对分子质量为31 318,重均相对分子质量为81 760,相对分子质量分散指数为2.61;制得的PPIA在522℃左右分解速率达到最大值,质量损失率约52%,具有良好的耐热性。

A stable diamine monomer, N,N′-bis(trimethylsilane) p-phenylenediamine(BTMSP), was synthesized by the reaction of trimethylchlorosilane(TMCS), an organosilicone protector, with p-phenylenediamine(PPD), and was reacted with m-phthaloyl chloride(IPC) to synthesize poly(p-phenylene isophthalamide)(PPIA) by low temperature solution polycondensation. The structure and properties of PPIA were characterized. The results showed that TMCS used to protect PPD was highly feasible;compared with that with no protective agent, the polymerization time of BTMSP and IPC was shortened in presence of protective agent, and the inherent viscosity of PPIA was up to 1.35 dL/g after 3 h of reaction;the polymer synthesized from BTMSP conformed to the basic structure of PPIA, and TMCS was not involved in the composition of the polymer;the number average relative molecular mass of the obtained PPIA was 31 318, the weight average relative molecular mass was 81 760, and the relative molecular mass dispersion index was 2.61;the prepared PPIA had the maximum decomposition rate and the mass loss rate about 52% at about 522 ℃, indicating a good heat resistance.