Effect of Silane on Viscoelastic Behavior of Epoxy under Hygrothermal Conditions

Abstract

This study examines impact of (3 � Glycidyloxypropyl) trimethoxysilane coupling agent on epoxy resin by matrix modification. Different weight percentages of silane were added to neat resin to investigate how silane�s reaction with epoxy changes important properties of the material before and after moisture absorption. Nanoindentation was employed to evaluate mechanical properties taking into account viscoelastic nature of the material being studied. Water degradation of samples were conducted both at room temperature and 50 ? to gain insight into changes caused by absorption of water and effect of increase in temperature. It was observed that silane degraded various properties of neat resin such as elastic modulus, hardness and creep resistance. Differential scanning calorimetry (DSC) results indicated that glass transition temperature (Tg) of the material was also lowered. However, the most interesting observation was that for 2 wt. % silane samples which were subjected to 50 ? water degradation there was increase in creep resistance as well as glass transition temperature. Fourier transform infrared spectrospcopy (FTIR) was used to analyze chemical interaction which could have been attributed as the reason behind possible increase in cross linking of epoxy under sub boiling water degradation environment.