电子束固化苯并噁嗪及其复合材料研究

High performance polymeric matrix fibrous composites (PMFCs) are widely used in aerospace structural applications because of their light-weight, high specific strength and corrosion resistance. Autoclave curing of composite structures, dominating in current high-performance composites industry practice, is expensive, time and energy consuming, and size limited. Therefore, there is a critical need for the development and characterization of new out-of-autoclave (OOA) composite processes for the future manufacture of large integrated structures. Electron beam (EB) curing of PMFCs is a nonthermal, OOA curing method that offers the many advantages over thermal curing to fabricate large integrated structures for high performance applications. Although EB curing of PMFCs was explored over 30 years ago, the resin systems that have been widely studied as EB curable composites are only epoxies and acrylates. The new development of EB radiation responsive resins or oligomers, initiators and formulation systems tailored for the needs of composite matrices is required. Benzoxazines is one of a rare few new resins commercialized in the past 30 years. Their excellent thermal, chemical, electrical, mechanical, physical properties and rich molecular design flexibility make them attractive alternatives for to existing high performance composite applications. However, one of the major disadvantages of the benzoxazines is the high temperature needed for complete cure. Therefore, to lower the cure temperature of benzoxazine became the axis of future research. The objective of this novel research is to first-ever develop a fundamental understanding of EB curing of benzoxazines and their composites. The various factors such as EB processing parameters, the temperature-time rise characteristics, chemical structure of monomers, initiator types and concentrations, impurities, fiber types and post-cure treatment will be correlated with the structures and properties of cured polybenzoxazines and their composites. The relations between EB processing parameters, the resultant physical and chemical structure and the performance of EB cured benzoxazines and their composites will be carefully studied. The cure mechanism and kinetics of E-beam cured model benzoxazines will be characterized. This research will develop a new method for nonthermal, fast cure of benzoxazine resins and their composites. Meanwhile, a new family of EB radiation responsive resin systems for composite matrices will be explored. It is not only a breakthrough for benzoxazine chemistry and its applications, but also a significant progress toward resolving the materials barriers of EB curing technique for future OOA manufacture of large integrated structures for high performance applications.

非热压罐固化和快速整体成型是未来高性能树脂基复合材料成型与制造的发展趋势。电子束（EB）固化具备成本低廉、快速高效、节能环保等特点，被认为是实现复合材料非热压罐固化和快速整体成型的关键技术之一。可有效EB固化的高性能树脂体系种类极少，相关研究匮乏，严重制约了EB固化技术在复合材料成型中的应用。我们将首次开展EB固化苯并噁嗪及其复合材料的基础研究，阐释EB固化苯并噁嗪的聚合反应机理及反应动力学，揭示苯并噁嗪及其复合材料EB固化工艺-结构-性能之间的基本关系。通过对EB固化苯并噁嗪及其复合材料的基本特性研究和过程控制，完善固化工艺，为EB固化复合材料技术提供坚实的实验与理论基础。本项目将首次实现苯并噁嗪复合材料的低温快速固化，使苯并噁嗪树脂体系的固化加工手段多样化，也将大大丰富EB固化材料体系，使之更广泛地应用于材料快速成型与制造技术，实现苯并噁嗪树脂及EB固化技术在各自应用领域中的重大突破。

苯并噁嗪树脂是近几十年发展起来新型酚醛树脂，它除了具有传统酚醛树脂的高残炭、高热稳定性外，还具有高模量、低介电常数、低表面能等优异的性能。苯并噁嗪还具有一些明显的缺点，比如固化时间长、固化温度高，这也限制了它在复合材料中的进一步应用。电子束固化具备成本低廉、快速高效、节能环保等特点，被认为是实现复合材料非热压罐固化和快速成型的关键技术。可有效EB固化的高性能树脂体系种类极少，相关研究匮乏，严重制约了EB固化技术在复合材料成型中的应用。.经过四年多年的探索与研究，很好地完成了电子束固化苯并噁嗪的主要研究内容，实现了苯并噁嗪单体的低温快速固化。主要总结如下：1、研究了不同结构的二苯基碘鎓盐的用量对苯并噁嗪热催化固化反应体系的稳定性和力学性能研究，证实了适量催化剂的加入不会影响体系的热性能与力学性能；用原位红外光谱法，证实了热引发条件下主要生成酚醛树脂型聚合物。2、研究了电子束辐照条件对苯并噁嗪单体和苯并噁嗪溶液的固化行为的影响，结果表明电子束辐照苯并噁嗪的0.05mol/L的三氯甲烷溶液能得到最好的固化效果，噁嗪环的开环率能达到86-97%；3、通过在线温度检测发现，电子束辐照时的最高温度低于100 oC，排除了热引发噁嗪环开环聚合的可能；通过核磁氢谱表明，电子束辐照的苯并噁嗪树脂存在酚型和醚型两种开环方式； 4、研究了不同结构的苯并噁嗪对电子束辐照固化行为的影响，结果表明含活泼羟基和羟甲基的苯并噁嗪具有更好的固化效果。5、研究了电子束辐照条件对苯并噁嗪/环氧树脂体系的固化行为的影响。 .本项目发表研究论文六篇，五篇SCI论文，一篇DSCD论文。还有三篇SCI论文正在准备中。申请专利九项，其中三项已经授权。在这九篇专利中有四篇已经进行成果转换，转换总金额在30万元。总之本课题研究实现了苯并噁嗪树脂的低温快速固化，为苯并噁嗪在复合此料中的应用进一步扫清了障碍，同时进一步丰富了可EB固化的树脂基体。