EFFECT OF ALPHA-METHYL STYRENE ON CURING BEHAVIOR AND INTERFACIAL PROPERTIES OF GLASS-FIBER-REINFORCED VINYL ESTER RESINS

The curing behaviour of bismethacryloyl derivative of diglycidyl ether of bisphenol A (vinyl ester VE resin) containing styrene and alpha-me thyl styrene (MS) as reactive diluents was studied. Delayed curing was observed in samples containing increasing proportions of MS. Interfac ial shear stress of untreated as well as gamma-methacryloyloxypropyl t rimethoxy silane (MTS) treated, glass fibre-reinforced VE resin compos ites were measured by single fibre technique. In comparison to untreat ed glass fibres, a 30-50% increase in interfacial shear stress was obs erved in composites based on MTS treated glass fibres. Addition of up to 5 wt.-% MS to VE resin did not affect the interfacial shear strengt h (ILSS). This behaviour was observed by using ILSS measurement of bot h glass fabric-reinforced composites as well as single fibre specimens . Further increase in MS to 15 wt.-% resulted in an increase in ILSS a nd bending stiffness as well as flexural strength.