【作者】 吴建元；

【导师】 顾媛娟；

【作者基本信息】 苏州大学 ， 材料学， 2010， 硕士

【摘要】 双马来酰亚胺(BMI)是高性能树脂的典型代表,其突出的综合性能(耐热性、介电性能、吸湿性能等)得到了人们的广泛关注。但是,作为一种热固性树脂,BMI树脂也存在固化物脆性大的问题,因此增韧改性一直是BMI树脂研究的重要研究内容。近年来,微胶囊增韧热固性树脂引起了人们的关注,同时可以赋予材料自修复等多功能,因此微胶囊在树脂体系中的应用日益受到重视。但是现有微胶囊的耐热性较低,限制了其在BMI树脂中的应用,因此开发具有优良耐热性的微胶囊并将其用于BMI树脂的增韧是一项有意义的研究工作。本论文通过原位聚合法,以2,6-二甲基苯酚(DMP)为囊壁材料,环氧树脂(DGEBPA)为囊芯,成功合成了一种新型的聚苯醚包覆环氧树脂微胶囊(PPO-MC),考察了不同参数对微胶囊形貌、尺寸、热稳定性及耐溶剂性的影响。研究结果表明最佳的合成PPO-MC的工艺为：以十二烷基硫酸钠(SDS)为乳化剂,反应温度为30℃,囊壁与囊芯的质量比为1：1.2。以最佳条件制得的PPO-MC具有良好的耐溶剂性和热稳定性,其初始分解温度在258℃左右。将PPO-MC应用于BMI/二烯丙基双酚A(BA)树脂体系中,研究了不同粒径、含量的微胶囊对BMI/DBA树脂反应性、力学性能、热性能、介电性能及吸湿性能的影响。研究结果表明,PPO-MC的加入能促进树脂的固化,PPO-MC含量越高,催化作用越明显,但与微胶囊粒径大小关系不大。树脂体系的力学性能随PPO-MC含量的增加先升高后降低,并且PPO-MC的粒径越小,增韧效果越明显。当加入5wt%粒径为80μm的微胶囊时,改性体系具有最佳的力学性能,即改性树脂的冲击强度和弯曲强度分别达到14.8KJ/m2和170MPa,是BMI/BA树脂相应性能的1.15和1.2倍。改性树脂体系的分解温度随微胶囊含量的增加而降低,但玻璃化转变温度有所提高。此外,微胶囊含量和粒径对树脂的介电常数、介电损耗与吸湿率产生相似的影响,即均随PPO-MC含量的增加而降低,但当含量达到一定值后,上述性能又有所升高；在相同含量下,PPO-MC的粒径越小,体系的介电常数、介电损耗和吸水率越小。更多还原

【Abstract】 Being a typical representative of high performance thermosetting resins, bismaleimide (BMI) resins have gained wide attention due to its outstanding integrate properties (such as thermal, dielectric and mechanical properties as well as water absorption). However, as a thermosetting resin, the biggest drawback of BMI resins is their brittleness. Recently, microcapsules can endow materials multi-functions such as toughening and self-healing, and thus have been employed to enhance the performance of polymer. But present microcapsules usually have low thermal-degradation temperature, and can not be applied in developing high performance resins including BMI resins. Hence, synthesizing new microcapsules with better thermal stability, and then discussing its modification of BMI resins is of great interesting.A novel kind of polyphenylene oxide (PPO) microcapsules filled with epoxy resin (PPO-MC) was synthesized by in situ polymerization, of which 2,6-dimethyl-1, 4-phenylene oxide (DMP) is the shell and diglycidyl ether of bisphenol A (DGEBPA) epoxy resin is the core. The effect of different process parameters on surface morphology, size distribution, thermal stability and solvent resistance of microcapsules was investigated. Results illustrate that the optimum synthesizing parameters for microcapsules are:sodium dodecyl sulphate (SDS) is used as the surfactant, the reaction temperature is 30℃, the weight ratio of DMP to DGEBPA is 1:1.2. With the optimum parameters, the synthesized PPO-MC exhibits good thermal stability, its initial degradation temperature is about 258℃.PPO-MC with various diameters and contents was added into BMI/BA resin to develop high performance modified BMI/BA/PPO-MC systems, and the effects of diameter and content of PPO-MC on the processing characteristics, mechanical properties, thermal stability, dielectric properties and water resistance of BMI/BA/PPO-MC resins were investigated in detail. The reactivity of BMI/BA can be catalyzed by the addition of PPO-MC, and the effect becomes pronounced with more PPO-MC content, while the diameter of PPO-MC does not affect the curing of BMI/BA. With increasing the content of PPO-MC, both the impact and flexural strengths increase firstly and then decrease; with the same content of PPO-MC, the smaller the mean diameter of PPO-MC, the better mechanical properties are. The modified BMI/BA resin containing 5wt% PPO-MC with a mean diameter of 80μm has the optimum mechanical properties, specifically, its impact and flexural strengths are about 14.8KJ/m2 and 170MPa, respectively, about 1.15 and 1.20 times of those of original BMI/BA resin. Modified BMI/BA resins have higher glass transition temperature than original BMI/BA resin, while the former has slightly lower thermal-degradation temperature than the later. In addition, the diameter and content of PPO-MC has similar effect on the dielectric constant and loss as that on water absorption, the dielectric constant and loss as well as water absorption initially decrease with the increasing of PPO-MC content, and then increase with further increased PPO-MC content; with the same content of PPO-MC, the smaller the mean diameter of PPOMC, the smaller dielectric constant and loss as well as water absorption are.更多还原