Fabrication and characterization of co-polyimide fibers containing pyrimidine units
Fabrication and characterization of co-polyimide fibers containing pyrimidine units
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含嘧啶单元的共聚酰亚胺纤维的制备与表征
DOI：
10.1007/s10853-017-1099-1
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发表时间：
2017-08-01
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
以自制的2，5-二（4-氨基苯基）嘧啶二胺（PRM）为原料，与4，4 ′-二氨基二苯醚（ODA）和芳香族3，3 ′，4，4 ′-联苯四甲酸二酐（BPDA）反应，合成了一系列含嘧啶环的共聚聚酰亚胺（co-PI）。采用两步法湿法纺丝工艺，包括挤出、凝固、洗涤、干燥、热亚胺化和热拉伸工艺，制备了一系列共聚酰亚胺纤维。讨论了湿法纺丝过程中共聚PAA纤维的取向结构及其对共聚PI纤维热机械性能的影响。发现了一个有趣的现象，即共聚酰亚胺纤维的玻璃化转变温度（T（g）s）随取向因子的增加而降低，并在前人工作的基础上对这一现象进行了解释。二维广角X-射线衍射光谱的最终共PI纤维表明，样品具有较高的PRM含量显示出高度取向和良好有序的晶体结构，这占增强的机械性能时，将PRM部分。PRM/ODA摩尔比为6/4的共聚PI纤维的拉伸强度和模量分别为3.1和90 GPa，显示出在轻质先进复合材料中的巨大潜力。
A series of co-polyimides (co-PIs) containing pyrimidine rings were synthesized by reacting the self-synthesized diamine 2,5-bis(4-aminophenyl)-pyrimidine (PRM) with commercial 4,4'-diaminodiphenyl ether (ODA) and aromatic 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA). A series of co-PI fibers were produced using a two-step wet-spinning method, including extrusion, coagulation, washing, drying, thermal imidization and hot-drawing processes. Orientation structures of the precursor co-PAA fibers formed in the wet-spinning process, and their effects on the thermomechanical properties of the as-spun co-PI fibers were discussed. An interesting phenomenon has been found that glass transition temperatures (T(g)s) of as-spun co-PI fibers decreased with increasing orientation factors, which was explained based on some previous works. Two-dimensional wide-angle X-ray diffraction spectra of the final co-PI fibers showed that samples with higher PRM contents show highly oriented and well-ordered crystalline structures, which account for the enhanced mechanical properties when incorporating PRM moieties. The co-PI fiber with the PRM/ODA molar ratio of 6/4 showed an optimum tensile strength and modulus of 3.1 and 90 GPa, respectively, showing a great potential in light advanced composites.