Phosphorylated CNSL prepolymer as a foundry sand core binder

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">The performance of phosphorylated cashew-nut shell liquid prepolymer (PCNSL) as a core binder in foundry applications is studied. Moulding properties such as strength and permeability and casting characteristics such as surface quality of castings, core-metal reactions, core collapsibility and anti-damping behaviour are analyzed. PCNSL gave superior performance in all these factors when compared to other system of binders such as sodium silicate. Studies based on IR spectra and SEM on the nature of bonding between sand and PCNSL indicate involvement mostly of physical and mechanical interactions rather than chemical bonding. The formation (during casting) of higher content of char (due to the presence of phosphate group in the resin) with open porous structure as revealed by SEM is thought to give better collapsibility to the system.</span>