Plasticization of methylolacrylamide copolymers by grafting onto a styrene–butadiene backbone

Abstract

AbstractThe development of a methylolacrylamide–styrene copolymer into a product suitable for use as a general‐purpose industrial or appliance enamel has been described; the choice of a suitable means of plasticization is emphasized. The incorporation of ethyl acrylate in the copolymer is expensive and was found relatively inefficient. Plasticization by blending the copolymer with tricresyl phosphate, butyl cyclohexyl phthalate, or dioctyl phthalate gave excessive thermoplasticity. Attempted plasticization by blending the copolymer with conformationally different macromolecules failed owing to incompatibility; this was overcome by reacting the macromolecules with the acrylic copolymer instead of blending: First, a butyl alcohol modified methylolacrylamide–styrene copolymer was transetherified with cetyl alcohol and in a second synthesis, transetherified with coconut oil monoglyceride. Third, an acrylamide–styrene–acrylic acid copolymer was esterified by the same monoglyceride, methylolated, and then butylated. Finally, an acrylamide–styrene copolymer was copolymerized and grafted onto a styrene–butadiene copolymer. This latter type of plasticization, which should be a general and valuable method, was supplemented by plasticization from dioctyl phthalate and yielded, after heating, economical and durable films with good mechanical properties.