MWNTs/PBO共混纤维的制备及性能

通过原位分散方法将不同含量的多壁碳纳米管（MWNTs）引入聚对苯撑苯并二噁唑（PBO）聚合体系，共混产物采用液晶纺丝法纺制成高性能MWNTs/PBO纤维。用偏光显微镜观察了MWNTs的分散状况，发现将MWNTs先预分散在多聚磷酸（PPA）中再添加可以有效地改善其分散性，热失重分析仪、强力仪研究了纤维的热稳定性能和力学性能。结果表明，MWNTs质量分数为2%的共混纤维的拉伸强度和模量分别达到4.69 GPa和128.8 GPa，比相同卷绕速度下PBO纤维提高了24.2%和23.5%，起始热分解温度也从668.9℃提高到700.8℃。MWNTs的质量分数达到5%时由于团聚严重，降低了PBO的可纺性，影响了纤维的性能。 

Preparation and properties of MWNTs/PBO blend fiber

With in-situ bending various contents of multi-wall carbon nanotubes (MWNTs) were introduced into the solution polymerization system of poly (p-phenylene benzobisoxazole) (PBO)，and the blends were spun into high performance fibers via liquid crystal spinning. Under the observation with a polarized optical microscope，it is found that the pre-diffusion in poly(phosphoric acid) (PPA) instead of direct adding MWNTs will promise better dispersion in PBO. The mechanical and thermal properties of PBO and MWNTs/PBO fibers were tested by a tensile strength tester and thermogravimetric analyzer. The results show that the tensile strength and modulus of the blend fiber containing 2% MWNTs are 4.69 GPa and 128.8 GPa respectively，which are approximately 24% and 23.5% higher than of the pure PBO fibers. The decomposition temperature of the composites is also improved from 668.9℃ to 700.8℃. When the mass fraction increases to 5%，MWNTs aggregate seriously，giving a negative influence on the spinnability of MWNTs/PBO blend and the mechanical properties of the blend fibers.