Mechanical Properties and Toughening of a Polymethylsilsesquioxane Network

Abstract

AbstractPolysilsesquioxanes are finding wider uses in microelectronics. However these materials are brittle and their mechanical behaviors need to be better understood. In this paper the mechanical properties of a cured methyl silsesquioxane network are studied and they are found to vary strongly with curing conditions. In the investigated curing temperature range there seems to be a correlation between the fracture toughness (KIc) and the viscoelastic transitions, which are affected by the network crosslink density. A higher crosslink density suppresses the cc and β transitions and reduces the KIc. A toughening approach is designed and its applicability is demonstrated by the increased fracture toughness.