@phdthesis{Pfau2018, type = {Master Thesis}, author = {Benjamin Florian Pfau}, title = {Introduction of a Process for Fracture Toughness Testing of Plastics and Investigations on the Influence of the Graphene Nano-platelet Content on Fracture of an Epoxy Resin System}, year = {2018}, abstract = {This thesis focuses on the introduction of a process for the fracture toughness testing of epoxy resin systems, in the light of the linear elastic fracture mechanic approach. Based on the requirements of ISO 13586, SENB-specimen were designed and especially the precracking process was analysed and the tapping process was optimized by designing and testing a drop-weight device. After successful validating the test process using specimen made of Araldite LY556, the in uence of GNP loading on the fracture toughness was analysed. The pure epoxy showed a KIc of 0.73 MPap m, being perfectly in line with the manufacturers datasheet. A peak in fracture toughness of 0.83 MPap m was archived at 1 wt\% and a loading rate of 10 mm/min, showing a decreasing trend as the loading is increased further. As the loading rate is increased, the fracture toughness reduces slightly for 0.5 wt\% and 2 wt\% GNP, but drops signi� cantly for 1 wt\% GNP obliterating the peak. The load vs. displacement curves showed quasi-brittle material behaviour. The fracture surfaces were analysed using SEM and while the neat resin did not show any features, did the reinforced samples show pattern of crack pinning in connection with bridging and pull-out. The resulting improvement is less signi� cant as observed by other researchers for larger GNPs. This is in line with the general idea, that small particles are not able to yield as high improvements, but the signi� cant decrease for higher loading rates is not observed or described so far. It is suspected that tests at lower loading rates (e.g. 1 or 0.5 mm/min) show an even higher fracture toughness.}, language = {en} }