Synthesis and Polymerization of Multifunctional Monomers with Hemiacetal Ester Linkages for Degradable Thermosetting Resin

The reaction of methacrylic acid with vinyl ethers with an epoxy group, 4-vinyloxybutyl glycidyl ether (VBGE) and cyclohexane dirnethanol vinyl glycidyl ether (CHDMVG) provided two sorts of triple functional monomers with a polymerizable vinyl group, a curable epoxy group,and an acid-sensitive degradable hemiacetal linkage (GBEM and GMCHMEM, respectively).GBEM and GMCHMEM were polymerized with 2,2'-isobutyronitrile (AIBN) to give relatively high-molecular-weight soluble polymers. Poly(GBEM) and poly(GMCHMEM) were then cured through their pendant epoxy functions with amine curing agents at 100 'C for 2 h to produce the insoluble crosslinked poly(GBEM) and poly(GMCHMEM) thermosets. These cured thrmosets were glassy and tough polymers and underwent degradation to give poly(methacrylic acid) and crosslinking chain residues via acid-catalyzed hydrolysis of the hemiacetal ester linkages in the polymers at room temperature