High‐strength–high‐modulus polyimide fibers II. Spinning and properties of fibers
High‐strength–high‐modulus polyimide fibers II. Spinning and properties of fibers
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DOI：
10.1002/app.1986.070320122
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发表时间：
1986-07
影响因子：
3
通讯作者：
T. Kaneda;Katsura Toshio;Kanji Nakagawa;H. Makino;M. Horio
中科院分区：
文献类型：
--
作者：
T. Kaneda;Katsura Toshio;Kanji Nakagawa;H. Makino;M. Horio
本系列第一部分中描述的基于3，3‘，4，4’-联苯基四甲酸二酸酐(BPDA)的聚酰亚胺在对氯苯酚中溶解，并在乙醇的凝固浴中纺丝成纤维。经300~500℃拉伸处理后，纤维的强度和弹性模量显著提高，拉伸强度可达26g/den(3.1 Gpa)，初始定伸应力大于1000g/den(120 Gpa)。因此，聚酰亚胺退火纤维的力学性能与芳纶纤维相当。聚酰亚胺纤维在空气和饱和水蒸气中的耐热性高于芳纶纤维。聚酰亚胺纤维的耐酸、耐紫外线(UV)性能优于芳纶纤维，但耐碱处理性能较差。退火后的聚酰亚胺纤维表现出明显的X射线衍射图。由BPDA和邻甲苯胺制得的聚酰亚胺纤维的链重复距离为20.5A，由BPDA和3，4‘-二氨基二苯醚制备的聚酰亚胺纤维的链重复距离为20.6A，综合考虑单体单元的尺寸和分子链的形状，链重复距离是合理的。两种聚酰亚胺纤维的X射线反射在假设晶胞的基础上得到了令人满意的指数化。
The polyimides based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) described in Part I of this series were dissolved in p-chlorophenol and spun into fibers using a coagulating bath of ethanol. The fibers as spun had in general low tenacities and low moduli, but a heat treatment at 300–500°C under tension produced a remarkable increase in strength and modulus, and fibers with a tensile strength of 26 g/den (3.1 GPa) and an initial modulus higher than 1,000 g/den (120 GPa) could be obtained. Thus, the annealed fibers of polyimides are comparable to aramid fibers in mechanical properties. To heating in air and in the saturated steam, the polyimide fibers showed higher resistance than the aramid fibers. The polyimide fibers surpassed the aramid fibers in resistance to acid treatment and ultraviolet (UV) irradiation, but were inferior in resistance to alkali treatment. The annealed fibers of polyimides displayed distinct X-ray diffraction patterns. The chain repeat distance of 20.5 A determined on the fibers of polyimide prepared from BPDA and o-tolidine, and 20.6 A determined on the fibers of polyimide derived from BPDA and 3,4′-diaminodiphenyl ether are reasonable when the dimensions of monomeric units and the shapes of the molecular chains are considered. The X-ray reflections of both polyimide fibers were indexed satisfactorily on the basis of postulated unit cells.