Rigid-rod polymers. 2. Synthesis and thermal properties of para-aromatic polymers with 2,6-benzobisthiazole units in the main chain
Rigid-rod polymers. 2. Synthesis and thermal properties of para-aromatic polymers with 2,6-benzobisthiazole units in the main chain
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DOI：
10.1021/ma50005a005
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发表时间：
1981-07
期刊：
影响因子：
5.5
通讯作者：
J. F. Wolfe;B. Loo;F. Arnold
中科院分区：
文献类型：
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作者：
J. F. Wolfe;B. Loo;F. Arnold
以2，5-二氨基-1，4-苯二硫醇二盐酸盐和辛酸为原料，在聚磷酸（PPA）中进行缩聚反应，合成了聚[（苯并[1，2-d：4，5-d ']双噻唑-2，6-二基）-1，4-亚苯基]（PBT）。聚合物浓度在5和10重量%之间的聚合混合物在转化的早期阶段是液晶的，并且适合于直接从PPA或在强酸中isolationand再溶解之后干喷湿纺成高模量/高强度纤维。由于使用<3%的聚合物浓度，使用浓度> 5%的液晶态聚合得到的溶液粘度低于保持各向同性的聚合。对于给定的分子量，较低的体积粘度有利于获得较高分子量的样品。在甲磺酸中测量的分离的PBT的特性粘度高达30.3dL/g。通过真空热重-质谱分析和在316和371 ℃下的等温老化测定，PBT显示出优异的热稳定性和氧化稳定性。刚性棒聚（苯并二噻唑）与不同程度的苯基取代的制备，但仅在低浓度下在某些混合溶剂中可溶。
Poly [(benzo [l, 2-d: 4, 5-d'] bisthiazole-2, 6-diyl)-l, 4-phenylene](PBT) was prepared by the polycondensation of 2, 5-diamino-l, 4-benzenedithiol dihydrochloride with terephthalicacid in poly (phosphoric acid)(PPA). Polymerization mixtures with polymer concentrations between 5 and 10 wt% were liquid crystalline at early stages of conversion and were suitable for dry-jet wet spinning into high-modulus/high-strength fibers either directly from PPA or after isolationand redissolution in strong acids. Polymerization in the liquid crystalline state by using concentrations> 5% gave lower viscosity solutions than polymerizations that remained isotropic, owing to the use of polymerconcentrations of< 3%. The lower bulk viscosity for a given molecular weight facilitated the attainment of higher molecular weight samples. Intrinsic viscosities of isolated PBT measured in methanesulfonic acid were as high as 30.3 dL/g. PBT showed excellent thermal and oxidative stability as determined by vacuum thermogravimetric-mass spectral analysis and isothermal aging at 316 and 371 C. Rigid-rod poly (benzobisthiazoles) with various degrees of phenyl substitution were prepared but were soluble only at low concentrations in certain mixed solvents.