PAI／羧基化MWCNTs复合材料的制备及流变学特性

摘要

The polyamide-imide (PAI) and PAI/carboxylated multi-wall carbon nanotube (MWCNTs-COOH) composites (NCs) were prepared via in situ polymerization. The thermal properties and relationship between temperature,concentration with rheological properties were studied by thermogravimetric analysis and rotational rheometer,respectively. The analysis results show that the thermal stability of PAI is increased when MWCNTs-COOH is added. The pure PAI solution is not sensitive to the shear rate and temperature. However,the NCs solution is more sensitive to shear rate than that of PAI solution and the shear thinning oc-curs. Still,the NCs solution can remain a stable liquidity at higher temperature or higher concentration and lower shear rate. Within the test range,loss modulus of the two solutions are higher than storage modulus,which indicates the viscosity dominates in the two solutions and gelation doesn′t occur. The effect of concentration,temperature and shear rate on the flow stability of PAI solution is weak,which gives a mild spinning condition,but the complex viscosity increases at high temperature and high angular frequency. NCs solution is suitable for wet-spinning with the condition of temperature of 75 or 90℃,concentration of 10%and low shear rate.%采用原位聚合的方法制备了纯聚酰胺酰亚胺(PAI)及PAI／羧基化多壁碳纳米管(MWCNTs-COOH)复合材料(NCs)，并采用热重分析仪和旋转流变仪分别研究了两种材料的热稳定性以及温度和溶液浓度对其溶液流变行为的影响。结果表明，MWCNTs-COOH的加入提高了NCs的热稳定性。纯的PAI溶液对剪切速率、温度不敏感；而NCs溶液对剪切速率较为敏感，发生了剪切变稀现象，但是在较高温度或较高浓度及低剪切速率下仍有稳定的流动性；在测试范围内，两种溶液体系的损耗模量高于储能模量，表明黏性占主导地位，不会发生凝胶现象。浓度，温度，剪切速率对PAI溶液的流动性影响较小，纺丝条件较为温和，但在高温高角频率区易发生复数黏度增大的现象；而在温度75℃或90℃、溶液浓度10%且剪切速率较低时，NCs溶液流动性稳定，适宜纺丝。