Abstract

A reactive diluent (ODA-PEPA) and a flexible phenylethynyl-terminated imide oligomer (PEI-PEPA) were designed and synthesized based on the 2,3,3’,4’-diphenyl ether tetracarboxylic acid dianhydride (a-ODPA), 3,4’-oxydianiline (3,4’-ODA), and 4-phenylethynylphthalic anhydride (PEPA). Solution blended systems with the addition of 5, 10, and 15 wt% ODA-PEPA to PEI-PEPA oligomer and their cured resin systems were prepared. Results showed that ODA-PEPA is semi-crystalline in nature. The T_g values of cured resins were improved from 273 °C to 280 °C by the addition of ODA-PEPA, due to the higher crosslink densities. In addition, rheological properties of blends showed lower melt viscosity and wider processing window, revealing improved melt processabilities for potential application in making advanced composites. The isothermal viscosity in 280 °C of PEI-PEPA containing 15 wt% ODA-PEPA reactive diluent decreased by two thirds, due to the low molecular weight of ODA-PEPA. The cured blends demonstrated high thermal stability and heat resistance. 5 wt% thermal decomposition temperatures (T_d5) of the cured blends were above 549 °C and 547 °C in N2 and air atmosphere, respectively. The char yield reported at 800 °C in N₂ atmosphere increased from 58.8% to 63.7 % with the addition of ODAPEPA. Meanwhile, the cured polyimides blends possessed good bond strength (> 9.3 MPa).

中文翻译：

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苯乙炔基封端的聚酰亚胺的共混改性的影响

摘要

基于2,3,3'，4'-二苯醚四羧酸二酐（a-ODPA），3设计并合成了反应性稀释剂（ODA-PEPA）和柔性苯乙炔基封端的酰亚胺低聚物（PEI-PEPA） ，4'-氧二苯胺（3,4'-ODA）和4-苯基乙炔基邻苯二甲酸酐（PEPA）。制备了向PEI-PEPA低聚物中添加5、10和15 wt％ODA-PEPA的溶液共混体系及其固化树脂体系。结果表明，ODA-PEPA本质上是半结晶的。第t_克通过增加ODA-PEPA，固化树脂的热值从273°C改善到280°C，这是由于较高的交联密度。另外，共混物的流变性能显示出较低的熔体粘度和较宽的加工范围，显示出改进的熔体加工性能，可潜在地用于制造高级复合材料。含有15 wt％ODA-PEPA反应性稀释剂的PEI-PEPA在280°C下的等温粘度降低了三分之二，这是由于ODA-PEPA的分子量较低。固化的共混物显示出高的热稳定性和耐热性。在氮气和空气中，固化共混物的5 wt％热分解温度（T _d5）分别高于549°C和547°C。N _2中在800°C时的炭产率加入ODAPEPA后，空气的含量从58.8％增至63.7％。同时，固化的聚酰亚胺共混物具有良好的粘结强度（> 9.3 MPa）。