High-performance polyimide fibers derived from wholly rigid-rod monomers
High-performance polyimide fibers derived from wholly rigid-rod monomers
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DOI：
10.1007/s10853-017-1932-6
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发表时间：
2018-04-01
影响因子：
4.5
通讯作者：
Zhang, Qinghua
中科院分区：
文献类型：
--
作者：
Gan, Feng;Dong, Jie;Zhang, Qinghua
聚酰亚胺纤维的力学性能不足是其广泛应用的主要障碍之一，尤其是在结构复合材料中用作增强体。本文以2，5-二(4-氨基苯基)-嘧啶(PRM)和对苯二胺(PPD)为原料，与3，3‘，4，4’-联苯四酸二酸酐(BPDA)共聚，制备了高强高模聚酰亚胺(PI)纤维。详细研究了化学结构(二胺摩尔比)对聚酰亚胺共聚纤维的分子堆积行为、微观形态和性能的影响。广角X射线衍射谱表明，相对于HOMO-BPDA/PRM和HOMO-BPDA/PPD-PI纤维，共-PI纤维具有较高的取向度和较低的侧向堆积有序度，当PRM/PPD摩尔比分别为5/5和4/6时，共-PI纤维的Herman取向度达到0.97。小角X射线散射(2D SAXS)表明，当PRM摩尔含量为50%时，共-PI纤维的内部结构最为致密。因此，与已报道的聚酰亚胺纤维相比，该共聚酰亚胺纤维具有更高的力学性能(拉伸强度为3.11 Gpa，定伸应力为144.2 Gpa)。同时，这些全刚性棒状聚酰亚胺纤维具有良好的热稳定性，其5%和10%的失重温度分别为548-565A℃和572-589A℃。这些聚酰亚胺纤维突出的综合性能使其成为未来纤维增强聚合物复合材料的有力候选者。
Insufficient mechanical properties are one of the major obstacles for the wide application of polyimide (PI) fibers, especially utilized as reinforcement in structural composites. In this work, the copolymerization of two rigid-rod diamines, 2,5-bis(4-aminophenyl)-pyrimidine (PRM) and p-phenylenediamine (PPD), with the 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was developed to fabricate PI fibers with high strength and high modulus. The effects of chemical structure (diamine molar ratio) on the molecular packing behavior, micromorphology as well as properties of the resulting co-PI fibers have been investigated in detail. Wide-angle X-ray diffraction spectra showed that co-PI fibers exhibited higher oriented structures with lower lateral packing order degrees in relative to both homo-BPDA/PRM and homo-BPDA/PPD PI fibers, and the Hermans' orientation degrees reached 0.97 for the two samples with PRM/PPD molar ratio of 5/5 and 4/6. Small-angle X-ray scattering (2D SAXS) patterns indicated that the co-PI fiber with the PRM molar content of 50% showed the densest inner structure. Accordingly, this co-PI fiber presented a higher mechanical performance (tensile strength of 3.11 GPa and modulus of 144.2 GPa) as compared to those PI fibers reported previously. Meanwhile, these wholly rigid-rod PI fibers exhibited excellent thermal stabilities with the 5 and 10% weight loss temperatures ranging from 548 to 565 A degrees C and from 572 to 589 A degrees C, respectively. The prominent comprehensive properties make these PI fibers strong candidates for the future fiber-reinforced polymer composites.