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聚苯并噁嗪的非均相结构及其碳纤维复合材料的固化动力学和界面性能研究

Study on the Structural Heterogeneity of Polybenzoxazine & the Cure Kinetics, Interfacial Properties of Polybenzoxazine/Carbon Fiber Composites

【作者】 信春玲

【导师】 余鼎声; 杨小平;

【作者基本信息】 北京化工大学 , 材料学, 2005, 博士

【摘要】 作为一类新型的类酚醛热固性树脂,苯并噁嗪最突出的优点是固化过程不需强酸或强碱固化剂,对设备无腐蚀作用,且固化过程无小分子放出,制品无孔洞,体积收缩率几乎为零,在高性能树脂基复合材料方面有巨大的应用潜力。深入理解苯并噁嗪的预聚体组成—交联结构—固化物性能之间的关系是优化聚苯并噁嗪性能的基础。目前关于聚苯并噁嗪交联结构的研究报导甚少。本论文认为聚苯并噁嗪交联结构的形成不仅受氢键作用的影响,还应考虑苯并噁嗪多官能团参与固化反应,以及自催化加速反应特征对交联结构形成的影响。因此,本论文通过在双苯并噁嗪预聚体中混入单苯并噁嗪预聚体,调节固化体系中参与反应的平均官能度数,从固化动力学出发,结合原子力显微镜、动态力学热分析等表征手段,对双酚A型聚苯并噁嗪的交联结构进行深入研究,初步探讨预聚体组成—交联结构—固化物性能之间的关系,以期为优化材料性能和进行分子设计提供依据;另一方面为了制备性能更优异的聚苯并噁嗪/碳纤维复合材料,优化复合材料的制备工艺,对聚苯并噁嗪/碳纤维复合材料的固化动力学进行了研究;最后初步探讨了几种商用碳纤维表面性能对复合材料性能的影响以便选择合适的碳纤维制备出界面性能更优的聚苯并噁嗪/碳纤维复合材料。 采用等温和非等温差示扫描量热仪(DSC)研究了双酚A型苯并噁嗪和双酚A型与苯酚型苯并噁嗪共混体系的固化过程,结果表明:固化过程中共混苯并噁嗪体系中形成的微凝胶数量和速率不同于双酚A型苯并噁嗪体系的,两体系的固化特征参数有较大差别,固化初期,共混苯并噁嗪体系的Avrami指数n大于双酚A体系的,共混体系中有更多的微凝胶生成和/或增长,当转化率相同时,共混体系的固化反应速率大于纯双酚A型苯并噁嗪体系的,且进入扩散控制阶段时,共混体系的转化率大于双酚A体系的。 原子力显微镜(AFM)用来观测聚苯并噁嗪浇铸体弯曲断面的微观相图,结果表明,聚苯并噁嗪交联网络为非均相结构,包括高交联密度的硬相分布在低交联密度的软相中,随苯酚型苯并噁嗪含量的增多,共混苯并噁嗪固化物中的高

【Abstract】 As one kind of newly developed phenolic thermosetting resin, polybenzoxazines have some excellent merits, such as near-zero shrinkage, no condensation by-products releasing and no strong catalysts needed upon curing. They could be widely used, as alternatives to traditional phenolic resins especially as matrices for high-property resin based composites. Fully understanding the relationship between monomer- network structure-properties of thermosetting resin is important for taking advantage of them. Nowadays the network structure of polybenzoxazines has been rarely reported. The Author of this paper think that the network formation of polybenzoxazine not only be influenced by hydrogen bond between intermoleculars or intramoleculars, but also by multifunction participating in cure reaction and the reaction molecular diffusion controlled. Therefore, the cure kinetics and the network formation were studied based on changing the average functionality by blending. bisphenol and phenol based benzoxazine. Then the network structure of polybenzoxazines and its effect on material properties were studied.

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