Abstract:

In order to upgrade the performance of poly(p-phenylenebenzobisoxazole) (PBO) materials and to promote its commercialization,a novel method for preparing PBO resin as developed by the homo-
polycondensation of a new AB-PBO monomer, 2-(4-methoxycarbonylphenyl)-5-amino-6-hydroxybenzoxazole (MAB), which was innovatively synthesized by the selective reduction of 4,6-dinitroresorcinol (DNR), then condensation-cyclization with 4-methoxycarbonylbenzoyl chloride and finaly catalytic-hydrogenation.The results showed that: (1) The intrinsic viscosity of PBO resin prepared from 98.2％ purity MAB was more than 10 dl/g in glassware,the total yield (based on DNR) was more than 64 %, polymerization time was shortened to 15 h and the operation was convenient; (2) MAB was exactly identified by ¹H-NMR, ¹³C-NMR, FT-IR and easily prepared at a total yield of 66%.The process has advantages of simple raw materials preparation, controllable selective reduction, one-pot condensation-cyclization, mild hydrogenation condition, and good economics.The selective reduction product: 4-Amino-6-nitroresorcinol hydrochloride (ANR•HCl) could be used as a key intermediate in the improvement of PBO performance; (3) The novel synthesis route could be developed into a new technique for commercialization.The new AB-PBO monomer, has outstanding stability (purity decreases only 0.12% after 270 days in the presence of air).There is no need for antioxidant agent in storage and polycondensation.MAB has equi-molar polycondensing group.The novel synthesis route is better than the AA-type 4,6-diamino resorcinol dihydrochloride plus BB-type terephthalic acid monomers co-polycondensation route.

Key words: 聚对苯撑苯并二噁唑, AB型PBO新单体, 2-(对甲氧羰基苯基)-5-氨基-6-羟基苯并噁唑, 4-氨基-6硝基间苯二酚盐酸盐

摘要：

为进一步提升聚对亚苯基苯并二噁唑（PBO）材料的性价比并促进其工业化，研究了以4,6-二硝基间苯二酚为原料，先选择还原制得4-氨基-6-硝基间苯二酚盐酸盐，进而与对甲氧羰基苯甲酰氯进行缩环合获得苯并噁唑化合物，再催化加氢合成AB型PBO新单体2-(对甲氧羰基苯基)-5-氨基-6-羟基苯并噁唑（MAB），最后自缩聚反应制备PBO的新路线和新方法.结果表明：该方法具有原料易得、反应条件缓和、中间体稳定等新技术优势.合成的PBO树脂总收率达64%、特性黏数η>10 dl&#8226;g^-1，新单体MAB的纯度>98%，具有稳定性优异和缩聚基团完全等当比等性质，以及均缩聚时间<20 h和过程易操作等技术特点，均为4,6-二氨基间苯二酚（DAR）共缩聚路线所难以比拟的.其综合经济性优于三氯化苯经DAR共缩聚的工业化路线，有望发展成易于实施PBO产业化的一项新技术.

关键词: 聚对苯撑苯并二噁唑, AB型PBO新单体, 2-(对甲氧羰基苯基)-5-氨基-6-羟基苯并噁唑, 4-氨基-6硝基间苯二酚盐酸盐