Thermal decomposition of methacrylate polymers containing tert-butoxycarbonyl moiety

In organic synthesis and polymer materials chemistry, a tert-butoxycarbonyl (BOC) group is often used as one of tools for the protection of functional groups. In this study, we carried out radical polymerization of 2-(tert-butoxycarbonyloxy)ethyl methacrylate (BHEMA) and copolymerizations of BHEMA with methyl methacrylate (MMA), n-butyl methacrylate (nBMA), isobutyl methacrylate (iBMA), tert-butyl methacrylate (tBMA), dodecyl methacrylate (DMA), alpha-methylstyrene (AMS), and limonene (Lim) as the 1,1-disubstituted ethylene monomers and investigated the thermal decomposition behavior of the obtained polymers. On the basis of the results of thermogravimetric (TG) analysis in nitrogen at the heating rate of 10 degrees C/min, it was revealed that the deprotection of the BOC group in the polymer side chains occurred at ca. 200 degrees C accompanying the quantitative elimination of isobutene and carbon dioxide, independent of the structures of the repeating units. The following main-chain decomposition of the residual copolymers resulted in a small amount of residue less than 1% at 500 degrees C. Poly(2-hydroxyethyl methacrylate) was synthesized via the deprotection of the BOC group of PBHEMA. (C) 2019 Elsevier Ltd. All rights reserved.