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Studies on high-performance wholly aromatic polyamide fibers by means of molecular design

高性能全芳香聚酰胺纤维的分子设计研究

基本信息

批准号：
63470093
负责人：
TAKAYANAGI Motowo
金额：
$ 4.42万
依托单位：
Kyushu Sangyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

1. For the purpose of realization of high-performance para-aramid fibers, in place of poly(p-phenylene terephthalamide)(PPTA), novel aramids composed of di- or ter-phenylene rings including pyrazine ring were molecular-designed and realized. The polymers were soluble in sulfuric acid and formed liquid-crystal.2. Both schemes of syntheses were tried: one is use of p-cyanoacetophenone as starting material, which was brominated, dimerized and hydrolysed to obtain terphenyl monomer, 2,5-bis(4-carboxyphenyl)pyrazine, and the other is to synthesize biphenyl monomers, 2-(carboxvDhenvl)-5-carboxypyrazine or 2-(carboxyphenyl)-5- aminopyrazine. These monomers were condensation-polymerized with p-phenylenediamine in a solvent of N- methylpyrrolidone and calcium dichloride.3. The para-aramid of terphenyl type, using 2,5-bis(4-carboxyphenyl)pyrazine was 2.01 dL/g of intrinsic viscosity and its weight loss temperature at 10% was 545ﾟC. The polymer was soluble in pure sulfuric acid and formed liquid- … More crystal above ca 8 % according to the phase diagram. The range of liquid crystal is, however, narrower compared with that of PPTA and easily crystallized, which resulted in the difficulties of spinning of fibers. From the X-ray structure obtained from the oriented thin film of terphenyl aramid the modulus was evaluated 310 GPa which amounts to about 1.6 times that of the PPTA. This evaluation is along with the expectation of molecular design. To improve the faults of fast crystallization rate and rapid relaxation of liquid crystal of terphenyl type aramid, two kinds of monomers of biphenyl type aramids were synthesized.4. Multiphenyl aramid was found to improve modulus compared with the existing aramids but its processabilty was extremely difficult. The increase of the fraction of pyrazine ring in the monomeric unit brings more stable liquid trystal phase than PPTA, which enables easy spinning. Two types of such aramid monomers were synthesized but the very low yield did not allow satisfactory evaluation of polymer properties as fiber at present. Less

1. 为了实现高性能对位芳纶纤维，分子设计并实现了由二亚苯基或三亚苯基环（包括吡嗪环）组成的新型芳纶代替聚对苯二甲酰对苯二胺（PPTA）。聚合物溶于硫酸并形成液晶。2．尝试了两种合成方案：一种是以对氰基苯乙酮为原料，经溴化、二聚、水解得到三联苯单体2,5-双(4-羧基苯基)吡嗪；另一种是合成联苯单体2-(羧基苯基)-5-羧基吡嗪或 2-(羧基苯基)-5-氨基吡嗪。这些单体与对苯二胺在N-甲基吡咯烷酮和二氯化钙溶剂中进行缩聚。 3．使用2,5-双(4-羧基苯基)吡嗪的三联苯型对位芳纶的特性粘度为2.01dL/g，10%失重温度为545℃。根据相图，该聚合物可溶于纯硫酸并形成约 8% 以上的液态晶体。但液晶的范围较PPTA窄，且容易结晶，导致纤维纺丝困难。根据由三联苯芳族聚酰胺的取向薄膜获得的X射线结构，评估模量为310GPa，相当于PPTA的约1.6倍。这一评价与分子设计的预期是一致的。针对三联苯型芳纶结晶速度快、液晶弛豫快的缺点，合成了两种联苯型芳纶单体。 4．人们发现，与现有芳纶相比，多苯基芳纶可以提高模量，但其加工性能极其困难。单体单元中吡嗪环比例的增加带来了比PPTA更稳定的液相，从而易于纺丝。合成了两种类型的芳族聚酰胺单体，但收率非常低，目前无法对作为纤维的聚合物性能进行令人满意的评估。较少的