含1,3,5-三嗪芳香二酸及其可溶性聚芳酰胺的合成

以2,4-二氯-6-苯基-1,3,5-三嗪为原料,通过傅克和氧化反应制备了一种新型芳香二酸2,4-二(4-甲酸基苯基)-6-芳基-1,3,5-三嗪(PTDA),并采用1H-NMR,FTIR,MS和元素分析等对其结构进行了表征.利用正交试验,重点考察了氧化反应条件对产率的影响,结果表明反应温度为25℃、反应时间为8 h、HAc与H2SO4摩尔比为10∶1、CrO3与PTDA配比为4∶1时,氧化产率最高,达81.3%.以PTDA和间苯二胺(BD)为原料,制备了新型含1,3,5-三嗪聚芳酰胺PPA,其特性黏数为0.49 dL/g.该聚酰胺表现出较好的溶解性能以及优异的热稳定性和机械性能,室温下可溶于N-甲基-2-吡咯烷酮、N,N-二甲基乙酰胺等溶剂中,由其溶液可制得透明薄膜;玻璃化转变温度达315℃,氮气中起始分解温度T5%为493℃,700℃下残炭率高达59%;薄膜的拉伸强度为82 MPa,断裂伸长率在8.2%,起始模量为2.3 GPa.

SYNTHESIS OF A 1,3,5-TRIAZINE-CONTAINING AROMATIC DIACID MONOMER AND ITS SOLUBLE AROMATIC POLYAMIDES

The synthesis,characterization and properties of phenyl-1,3,5-triazine functional monomers and aromatic polyamides are described.A novel aromatic diacid,namely 4,4′-(6-phenyl-1,3,5-triazine-2,4-diyl)dibenzoic acid(PTDA) was successfully prepared by a two-step reaction including Friedel-Crafts reaction and oxidation starting from 2,4-dichloro-6-phenyl-1,3,5-triazine(DCPT).Its chemical structure was characterized by1H-NMR,FTIR,MS and Elemental analysis.Optimal conditions of the oxidation were chosen on the basis of the yield by using orthogonal experiments with respect to oxidizer content,solvent ratio,heating temperature and reaction time.The reaction,which was achieved at the temperature of 25℃ for 8 h with a CH3COOH/H2SO4 ratio of 10 and a CrO3/PTDA ratio of 4,gave the targeted product with a highest yield of 81.3%.A new aromatic polyamide(PPA) with an inherent viscosity of 0.49 dL/g was obtained by direct phosphorylation polycondensation of PTDA with benzene-1,4-diamine.The obtained polymer possesses good solubility.It is readily soluble in N-methylpyrrolidone,N,N-dimethyl acetamide(DMAc) and sulfolane,and can be easily cast into transparent thin films.Such polymer exhibits glass transition temperature(Tg) up to 315℃,and possesses excellent thermal and thermo-oxidative stability without significant weight loss up to temperatures of approximately 500℃.Its decomposition temperature for 5% mass-loss is in excess of 493℃ in nitrogen and it retains 90% weight at round 520℃.The obtained films exhibits attractable mechanical properties with tensile strengths of 82 MPa,elongation at break of 8.2% and initial moduli of 2.3 GPa.