Synthesis and radiation grafting modification of hydroxyl controlled AM/HEMA polymer microspheres

Abstract

The, smooth-faced, highly cross-linked, hydroxyl controlled, micrometer-sized polymer microspheres of acrylamide (AM) and 2-hydroxyethyl methacrylate (HEMA) were prepared by reverse suspension polymerization. The polymerization parameters showed considerable influence on the morphologies and dispersion of the polymer particles, such as the stirring rate, polymerization temperature, monomer loading, initiator concentration, and crosslinking agent concentration, which makes it flexible to control the hydroxyl number of AM/HEMA microspheres by controlling polymerization conditions. Subsequently, the polymer particles was radiated with 60Co γ-rays(dose rate: 4.0 kGy/h) in pure oxygen environment for 24 h, as a result, free radicals are generated on the surface of the polymer microspheres. Afterward, AM was allowed to be graft-polymerized on microspheres AM/HEMA in the manner of “grafting onto,” resulting in the grafted microspheres PAM–AM/HEMA. This work provides optimized parameters to fabricate micron-sized AM/HEMA microspheres, and further expands the functionalization of AM/HEMA microspheres and its application fields.