Preparation of intercross-linked poly(L-lactide) and epoxy resin using N-benzyl pyrazine hexafluoroantimonate

The overall goal of our study was to prepare the intercross-linked poly(l-lactide) (PLA) and epoxy polymer by using N-benzyl pyrazine hexafluoroantimonate (BPH) as a latent hardener. First, the glycidol end-functionalized PLA (Gly-PLA) polymer was prepared at quantitative yields by the polymerization of l-lactide (LA) with glycidol as an initiator in the presence of stannous octoate. Gly-PLA showed the predicted PLA molecular weight. The epoxide group in the chain end of the PLA segments was observed using ¹H nuclear magnetic resonance (NMR). The ring-opening polymerization of the epoxy group in Gly-PLA in the presence of BPH as a latent initiator yielded the polyether-g-PLA (PE-g-PLA), which was confirmed using ¹H NMR and gel permeation chromatography (GPC). We confirmed that BPH acted as a latent initiator for the polymerization of epoxide in the Gly-PLA polymer. The curing of the epoxy resin (bisphenol-A-type epoxide oligomers, DGEBA) and Gly-PLA was carried out with BPH as a latent hardener. The curing reaction quantitatively generated a solvent-insoluble gelled epoxy resin. The curing process of the DGEBA and Gly-PLA in the presence of BPH was monitored using differential scanning calorimetry (DSC), and the cured materials were characterized with infrared (IR) spectroscopy. The results indicated that the intercross-linked Gly-PLA and epoxy resin could be prepared using BPH as a latent hardener.