Assessment of Small Interactions and Structural Gradient at the Interface of Glass and Carbon Fibers Epoxy and Micro-composites by FTIR-Imaging and DSC Techniques

Abstract

Many complex reactions occur at the interface due to moisture absorption and temperature and very little information is available regarding the chemical deviation near the interface due to moisture absorption. The present work uses FTIR-imaging and modulated temperature DSC to assess the structural gradient at the interface due to hygrothermal ageing of glass/epoxy and carbon/epoxy composite materials. The specimens were conditioned at 50οC in hydrothermal chamber with 90% humidity for the duration of 50 hours. The samples were studied before and after the hydrothermal aging near the interface i.e. in the interphase region to evaluate the chemical changes from the bulk of the matrix phase by FTIR-imaging. Alternating DSC was also done to study the deviation in the glass transition temperature of FRP composites. Mechanical properties of composite materials are dependent on the properties of the interphase region and even small chemical deviation effect the overall performance of composite materials. It was observed that hygrothermal treatment leads to change in chemical spectra and glass transition temperature near the interface which ultimately leads to change in interface dominating properties.