Experimental investigation on characteristics of resole based phenolic resin

Abstract

In this study, characteristics of two different resole based phenolic resin being used in aerospace application were investigated. Phenolic resins were advanced by conditioning to bring down its point of trouble. At this stage both resins were separately impregnated with PAN based carbon fabric as reinforcement and evaluated their rheologyproperties. Residues of free phenol, free formaldehyde and sodium content in resins were estimated for both the resins and compared. Also other properties such as neat resin cure characteristics, resin characteristic frequencies, molecular weight distributions, char yield of resins were evaluated and compared. A conclusion is drawn from the test results that char yield is affected by purity of phenolic resin viz presence of unreacted free phenol and free formaldehyde. Also viscosity plays a vital role in wetting of the reinforcement resulting in better interlaminar shear properties.