Functionalized polycarbonates from dihydroxyacetone: insights into the immortal ring-opening polymerization of 2,2-dimethoxytrimethylene carbonate

Abstract

Functionalized polycarbonates derived from 2,2-dimethoxytrimethylene carbonate (TMC(OMe)₂) have been prepared with controlled molecular features by immortal ring-opening polymerization, under mild conditions (bulk, 60–90 °C), using various (metallo)organic/alcohol (diol) binary catalyst systems: the β-diiminate zinc complex [(BDI^iPr)Zn(N(SiMe₃)₂)] (BDI = CH(CMeNC₆H₃-2,6-iPr₂)₂), the aluminium triflate, or the organic bases 4-N,N-dimethylaminopyridine (DMAP), 1.5.7-triazabicyclo-[4.4.0]dec-5-ene (TBD) and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP), as catalyst precursors, combined with benzyl alcohol or 1,3-propanediol acting both as a co-initiator and a chain transfer agent. For the first time, well-defined α-hydroxy-ω-alkoxyester and α,ω-dihydroxy telechelic acetal-functionalized homopolycarbonates were thus prepared with molar mass up to 70 200 g mol⁻¹. These polymers were characterized at the molecular (NMR, SEC), thermal (DSC, TGA) and mechanical levels, and compared to conventional PTMC. P(TMC(OMe)₂) is a rigid and brittle polymer material (E = 3190 ± 70 MPa, ε_r = 9 ± 1%).