Preparation And Performance Of Poly(Decamethylene Terephthalamide)/Thermotropic Liquid Crystal Polymer Blend

As a high performance engineering plastic,Poly(decamethylene terephthalamide)(PA10T) has high temperature resistance and excellent mechanical properties. But PA10 T has very high viscosity during the melting processing. It leads to PA10 T poor processing performance and limits the application of PA10 T. In order to enlarge the application range of PA10 T, it is necessary to improve the processing performance of PA10 T. In this thesis, the processing performance of PA10 T was improved by adding a small amount o f thermotropic liquid crystal polymer(TLCP), and PA10T/TLCP blends had good mechanical properties. The effects of the amount of TLCP on the processing performance, mechanical properties and thermal performance of PA10T/TLCP blendswere studied, and the better formula was obtained. The rheological behavior and crystallization behavior of PA10 T and PA10T/TLCP blends were compared. The effects of TLCP on the rheological behavior and the crystallization behavior of PA10 T were analyzed deeply. PA10T/TLCP blends, which had good processing performance, were strengthened by the inorganic fillers. The resultant composites not only had excellent mechanical properties, but also had good processing performance.The effects of polyphenylene sulfide(PPS) and TLCP on the processing performance of PA10 T were compared, and TLCP was chosed to improve the processing performance of PA10 T, and prepared PA10T/TLCP blends.The effects of the amount of TLCP on the processing performance, mechanical properties and thermal performance of PA10T/TLCP blends were compared. The overall performance of PA10T/TLCP blend, in which the content of TLCP was 3 wt%, was the best. While the content of TLCP was 3 wt%, the PA10T/TLCP blend had very good processing performance. In the shear rate of 100s-1, its apparent viscosity was 189Pa·s, which was four times lower than the viscosity of PA10 T, and in the shear rate of 1000s-1, its apparent viscosity was 76Pa·s, which was three times lower than the viscosity of PA10 T.The mechanical properties of this PA10T/TLCP blend was also the best. Its tensile strength was 72.1MPa, and its blending strength was 102.2MPa, which were both higher than the strength of PA10 T.Moreover, compared with PA10 T,the heat distortion temperature(HDT) and thermal stability of this blend did not change much.In this thesis, the the rheological behavior and the crystallization behavior of PA10 T and PA10T/TLCP blend in which the content of TLCP was 3 wt% were compared. The melt of PA10 T and this PA10T/TLCP blend were both pseudoplastic fluid. The non-Newtonian Index(n) of the PA10T/TLCP blend was higher than n of PA10 T, and their flow activation energy were both high. The super-cooling degree(DT) and the half- crystallization time(t1/2) of this PA10T/TLCP blend were both lower than DT andt1/2 of PA10 T. It can be concluded that TLCP had played an important role of nucleating agent,and promoted the crystallization of PA10 T.In order to further improve its mechanical properties, the PA10T/TLCP blend was strengthened by different inorganic fillers.The mechanical properties and processing performance of the composites which had been strengthened by different inorganic fillerswerecompared. The enhancement effect of long glass fiber was the best. While the content of the glass fiber was 30 wt%, compared with PA10 T,the tensile strength of this composite was 121.0MPa, it increased by 71.6%. Its blending strength was 170.0MPa, it increased by 67.5%. Its blending modulus was 8.07 GPa, it increased by 243.4%. The HDT increased from 82.5℃ to 277℃. Moreover, the processing performance of the composites which had been strengthened by inorganic fillers was much better than the processability of PA10 T.