磷酸改性对对位芳纶纤维力学性能的影响和破坏机理  

Mechanical Behavior and Failure Mechanism of Phosphoric Acid Modified Para-Aramid Fiber

作　　者：陆赵情[1] 苏治平[1] 张美云[1] 郝杨[1] LU Zhaoqing SU Zhiping ZHANG Meiyun HAO Yang(College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science ＆ Technology, Xi＇an, Shaanxi Province, China, 710021)

机构地区：[1]陕西科技大学轻工科学与工程学院,西安710021

出　　处：《材料研究学报》2017年第8期597-602,共6页Chinese Journal of Materials Research

基　　金：陕西省科技统筹创新工程计划项目(2016KTCQ01-87);华南理工大学制浆造纸工程国家重点实验室开放基金(201333);陕西省教育厅重点实验室项目(12JS018)~~

摘　　要：研究了磷酸改性对对位芳纶(PPTA)纤维力学性能的影响和破坏机理。测量了PPTA纤维的单丝拉伸强度和力-位移曲线来评价其力学性能,用扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)和X射线衍射(XRD)等手段表征了PPTA纤维改性前后的表面形貌、化学结构和结晶度。结果表明,磷酸改性破坏PPTA纤维中韧性较高的皮层结构,使改性后纤维的力-位移曲线的最大断裂载荷点向低位移点偏移,拉伸强度降低。在磷酸改性过程中PPTA分子链中的酰胺键因发生水解反应而断裂,导致PPTA纤维的拉伸强度下降。磷酸改性使结晶不完善的皮层从纤维表面剥离,从而使纤维的结晶度升高,韧性降低;而过高的磷酸改性浓度(40%,质量分数)使纤维的结晶度降低,导致PPTA纤维的拉伸强度显著降低。Para-aramid fiber was modified with phosphoric acid（PA） and then was characterized by means of scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, and Xray diffraction（XRD）. The mechanical behavior of the modified fiber（PPTA） was evaluated via measurement of the tensile strength and force-displacement curve of monofilament. The results show that the maximal fracture force of the modified fibers shifted to lower displacement region in force-displacement curves and the tensile strength of the monofilament decreased due to the damage of the skin region of PPTA fiber induced by PA-modification. Some aramid groups can be hydrolyzed during PA-modification process, thus decreasing the monofilament tensile strength of the modified PPTA fibers. In addition, the crystallinity of the modified fibers was improved because the original para-crystalline skin region was peeled off from the surface of PPTA fiber by PA-modification, hence resulting in the decrease of toughness of PA-modified fiber. The monofilament tensile strength of PPTA fiber decreased remarkably once itwas modified with PA with concentration of higher than 40%（mass fraction）, which can be attributed to the decrease of crystallinity.

关 键 词：有机高分子材料 对位芳纶纤维 磷酸改性 力学性能 破坏机理 

分 类 号：TQ342[化学工程—化纤工业]