One-pot enzymatic polycondensation to telechelic methacrylate-functional oligoesters used for film formation

Abstract

Based on largely renewable monomers, an enzymatic one-pot polycondensation route towards functional oligomers with targeted molecular weights and end-groups was developed. This one-pot synthesis was performed by combining Candida antarcticalipase B (CALB), 2-hydroxyethyl methacrylate (HEMA), ethylene glycol, and divinyl adipate under reduced pressure (72 mbar) at 60 °C. The polymerization went to completion (>95% conversion for all monomers) within 24 h and the fraction of methacrylate end-groups was >90%. Three targeted dimethacrylate functional oligomers with molecular weights of 920, 1700 and 2500 g mol⁻¹ (degrees of polymerization 4, 8, and 13 respectively) were synthesized. The oligomer products were characterized by NMR, MALDI-TOF MS and SEC. The dimethacrylate functional oligomers were further UV homopolymerized or combined with a tetrathiol crosslinker to demonstrate the potential to produce novel networks with tunable thermal properties dependent on chain length of the telechelic building blocks. This research is the first to demonstrate methacrylate functionalization and condensation polymerization in a one step process, which expands the growing toolbox for polymer/material chemists towards an increased throughput in available macromonomers used in material design.