Quantification and modelling of the fracture & fatigue performance of nanoparticle-modified epoxies

粘接和复合材料越来越多地用于主要的结构应用，包括现在和未来的飞机设计。这些材料和接头的结构完整性至关重要，与韧性和抗疲劳性直接相关。热固性聚合物形成这些材料的基础，但高度交联，因此非常脆。事实上，这些材料在航空航天、汽车和电子等行业中的应用已经取得了重大进展，但这些材料的韧性和抗疲劳性较差。提高韧性的一个非常成功的途径是添加软颗粒和硬颗粒的组合，例如橡胶和二氧化硅，以形成“混合”材料。然而，常规地，这些二氧化硅颗粒的直径为数十微米，并且对于用于制造纤维复合材料的灌注工艺来说太大，因为它们被纤维从树脂中滤出。纳米颗粒由于其尺寸而适用于输液过程，其尺寸足够小以允许它们在输液期间在纤维之间流动并防止任何应变。此外，低粘度树脂对于有效灌注是必不可少的;并且与微米尺寸的颗粒不同，纳米颗粒在适当表面处理时不会增加树脂的粘度。该项目将量化添加纳米颗粒对橡胶增韧环氧树脂性能的影响。将制造一系列微观结构，实验研究将确定不同微观结构对断裂和疲劳性能的影响。这些微结构将被描述和建模。该模型将用于预测材料的韧性，其结果将用于优化纤维复合材料基体材料的微观结构。优化的材料将被制造成散装板和纤维复合材料。将测量断裂和疲劳性能，并将结果与当前复合材料的性能进行比较。

Adhesive bonding and composite materials are being used increasingly in major structural applications, including present and future aircraft design. The structural integrity of these materials and joints is critical and directly related to the toughness and fatigue resistance. Thermoset polymers form the basis of these materials, but are highly crosslinked and hence are very brittle. Indeed, already significant advances in the use of these materials in industries such as aerospace, automotive and electronics are limited by the poor toughness and fatigue resistance. A very successful route to improve the toughness is to add a combination of soft and hard particles, e.g. rubber and silica, to form a 'hybrid' material. However, conventionally these silica particles are tens of microns in diameter, and are are too large for use with infusion processes for the manufacture of fibre composites, as they are strained out of the resin by the fibres. Nanoparticles are suitable for infusion processes due to their size, which is small enough to allow them to flow between the fibres during infusion and prevent any straining. Further, low viscosity resin is essential for efficient infusion; and nanoparticles, unlike micron-sized particles, do not increase the viscosity of resin when suitably surface-treated. This project will quantify the effect of the addition of nanoparticles on the performance of rubber-toughened epoxy. A range of microstructures will be manufactured, and experimental studies will establish the effect of the different microstructures on the fracture and fatigue performance. These microstructures will be described and modelled. The models will be used to predict the toughness of the materials, and the results will be used to optimise the microstructure of the matrix material for a fibre composite. The optimised material will be manufactured, as both a bulk plate and as a fibre composite. The fracture and fatigue performance will be measured, and the results will be compared with the performance of current composite materials.