N,N-二甲基乙酰胺/氯化钙体系对热致液晶聚芳酯纤维结构及性能的影响

Influence of N,N-dimethylacetamide/CaCl_2 system on structure and properties of thermotropic liquid crystal polyarylate fibers

为提高热致液晶聚芳酯(TLCP)纤维与基体材料的界面黏结性能,同时保持其优异的热学和力学性能,采用N,N-二甲基乙酰胺/氯化钙(DMAc/CaCl_2)体系对TLCP纤维进行表面改性制备TLCP/聚氨酯复合材料。借助单纤维万能测试仪、扫描电子显微镜、原子力显微镜、傅里叶红外光谱仪、X射线衍射仪、同步热分析仪和万能材料试验机等对改性前后的样品进行表征与分析。结果表明:TLCP纤维经DMAc/CaCl_2改性处理后表面条纹增多,平均粗糙度由96. 42 nm增至438. 60 nm;改性处理后的TLCP/聚氨酯复合材料的界面黏结性能有明显改善,平均剥离强度由0. 71 N/mm提高到1. 14 N/mm;改性后TLCP纤维分子结构无明显变化,纤维结晶结构不变,结晶度由69. 00%降至64. 45%;当DMAc体积分数不超过30%时,纤维的力学性能无明显下降。

In order to improve the interfacial bonding property between thermotropic liquid crystal polyarylate (TLCP) fibers and matrix material while maintaining the excellent thermal and mechanical properties of TLCP fibers,TLCP/polyurethane composites were prepared by surface modification of TLCP fibers with N,N-dimethylacetamide/calcium chloride (DMAc/CaCl 2) system.The TLCP fibers before and after modification were characterized and analyzed by means of single fiber universal tester,scanning electron microscope,atomic force microscope,Fourier transform infrared spectrometer,X-ray diffraction,synchronized thermal analyzer and universal material testing machine.The results show that,after being modified with DMAc/CaCl 2,TLCP fibers have increased surface fringes,and the average roughness increases from 96.42 to 438.60 nm.The interfacial bonding property of the modified TLCP fabric/polyurethane composites is improved significantly,and the average peeling strength increases from 0.71 N/mm to 1.14 N/mm.The modified TLCP fibers have no obvious change in the molecular structure and the crystal structure,and the crystallinity reduces from 69.00% to 64.45%.When the DMAc volume fraction does not exceed 30%,the mechanical properties of the fibers are not significantly damaged.