Evaluation of mechanical properties of sandwich structures with polyethylene terephthalate and polyvinyl chloride core

Sandwich structures are comprised of two external faces/skins (usually made of synthetic fiber/resin) and a core, being lightweight and with high stiffness. These structures when based on a foam core are commonly processed using liquid molding techniques. In this study, the light resin transfer molding process is used to inject the polymeric resin (vinyl ester) into the porous cavity between the impermeable core and the mold walls. The main goal of the present work is to study the effect of different types of cores (polyvinyl chloride (PVC) and polyethylene terephthalate) and faces (glass fiber cloths or mats) on the mechanical characteristics of the sandwich structures. Specimens were subjected to flexural, flatwise and edgewise compression, and Shore-D hardness testing. General comparison between the different core materials indicated higher flatwise compressive, flatwise tensile and shear strength of the PVC. However, the effect of the core on the properties of the sandwich structure, e.g. flatwise compressive and edgewise compressive strength, was much less evident.