Modification of phenol formaldehyde resin for improved mechanical properties

Abstract

Phenolic resins suffer from the presence of microvoids on curing. This often newlineleads to less than satisfactory properties in the cured resin. This disadvantage has newlinelimited the use of phenolic resins to some extent. This study is an attempt to improve newlinethe mechanical properties of the phenolic resol resins by chemical modification newlineaimed at reducing the microvoid population. With this end in view various themoset newlineresins synthesised under predetennined conditions have been employed for newlinemodifying phenolic resols. Such resins include unsaturated polyester, epoxy and newlineepoxy novolac prepolymers. The results establish the effectiveness of these resins for improving the newlinemechanical properties of phenolics. Experimental and analytical techniques used newlineinclude FTIR, DMA, TGA, SEM and mechanical property evaluation. While most of newlinethe modifier resins employed give positive results the effect of adding UP is found to newlinebe surprising as well as impressive.