Improvement of hydrophilicity of polypropylene by liquid‐phase mutual irradiation of acrylics

Abstract

N‐butanol was found to promote the inclusion of methyl acrylate and methyl methacrylate in polypropylene, but did not affect the uptake of acrylic acid in the polymer. Polymerization of the monomers was, however, not significantly affected by the use of this swelling agent. The monomer exchange process followed by a liquid phase mutual irradiation has proved to be very effective in enhancing the polymerization of all three monomers on polypropylene. Optimum radiation doses for effective polymerization of the monomers were found to be around 3.2 Mrad for methyl acrylate and around 4.8 Mrad for methyl methacrylate and acrylic acid. Surface wettability of the film and moisture regain of the fiber were tremendously improved with all monomers regardless of the swelling agent and temperatures. Also, a low radiation dose of 1.6 Mrad was as effective as the higher doses. Methyl acrylate and methyl methacrylate modified fibers showed no marked changes in strength and elongation, but did result in a harsher hand. Acrylic acid modified fibers increased greatly in elongation, decreased to a greater extent in strength, and softened in hand.