高相对分子质量PBO的聚合及其高性能纤维的成型

Synthesis of high molecular weight polybenzoxazole (PBO), spinning and properties of PBO fiber

以自行合成的4,6-二氨基间苯二酚盐酸盐(DAR)和商品对苯二甲酸(TPA)为单体原料,以多聚磷酸(PPA)为溶剂,制备了高相对分子质量PBO聚合物．研究了PBO聚合过程中TPA单体的粒径、溶剂的浓度以及搅拌器,聚合前脱除HCl的方式对PBO聚合和所得产物分子质量的影响．结果表明,TPA粒径小、聚合结束时PPA中P2O5的浓度维持在84％左右,有利于得到高相对分子质量的PBO聚合物．新型双螺带搅拌器能提高搅拌的效果,加压脱除HCl的工艺能有效地实施聚合的稳定控制,利用双螺杆挤出机同时完成了后聚合和液晶纺丝,得到了特性粘度([η])达到20-30 dL/g的PBO聚合物,采用干喷湿法成型制备出的金黄色的PBO纤维手感柔软、拉伸强度达到4．38 GPa．

High molecular mass polybenzoxazole （PBO） was synthesized successfully by polycondensation of 4,6-diamino resorcinol dihydrochloride （DAR） and terephthalic acid （TPA） in polyphosphoric acid （PPA） solvent. The effect of TPA particle size, the concentration of PPA and the stirrer frame as well as the way to dehydrochloride on PBO polymerization were investigated. It was found that the smaller particle size, the higher concentration （84%） of PPA availed PBO polymerization. The new designed stirrer could improve the efficiency of agitation. The created novel dehydrochlorination, i.e. restraining the foaming via pressure during the dehydrochlorination guaranteed the polymerization stability. The prepolymerization was carried out in reactors and post polymerization as well as liquid crystalline spinning was performed simultaneously by using twin screw extruder., which was invented to achieve the polymerization and spinning continuously high molecular mass PBO with an intrinsic viscosity in the range of 20dL/g to 30dL/g and high performance golden PBO fiber with tensile strength 4.38GPa was obtained.