高分子量聚对苯撑吡啶并二咪唑的制备

Preparation of High Molecular Weight Poly {2,6-dimidazo[4,5-b:4',5'-e]pridinylene-1,4(2,5-dihydroxy) phenylene}

以2,5-二羟基对苯二甲酸(DHTA)和2,3,5,6-四氨基吡啶(TAP)盐酸盐为原料,先合成2,5-二羟基对苯二甲酸-2,3,5,6-四氨基吡啶盐(TD盐),再由TD盐缩聚制得聚对苯撑吡啶并二咪唑(PIPD)。探讨了在聚合过程中补加反应单体以提高聚合物相对分子质量(简称分子量,下同)的可行性,考察了单体补加种类、反应时间、单体补加量和原料摩尔比对聚合物分子量的影响,最佳工艺条件为:原料摩尔比n(DHTA)∶n(TAP盐酸盐)=1.05∶1,在140℃时补加TAP盐酸盐,在180℃下反应4 h,单体补加量占TD盐质量的0.5%。聚合物由相对黏度间接表征其分子量,通过该法制备的聚合物相对黏度相比同条件下现有工艺提高近一倍。

2, 3,5,6-Tertraaminopyridine-2, 5-dihydroxy terephthalic acid was synthesized through neutralization reaction by using 2,3,5,6-tetraaminopyridine （TAP） hydrochloride and 2,5-dihydroxy terephthalic （DHTA） as raw materials. PIPD was polymerized from TD salt by condensation polymerization. The effect of various reaction parameters on polymerization, including the type of monomer, reaction time, additional amount of monomer and molar ratio of reactants, was investigated in detail. The optimal reaction conditions were confirmed ： the molar ratio of DHTA to TAP hydrochloride was 1.05：1 ,additional amount of TAP hydrochloride was 0. 5% of TD salt,which was added at 140 ℃, and the reaction proceeded at 180 ℃ for 4 h. Compared with existing processes,the relative viscosity of PIPD synthesized by this method increased approximately twice.