Bio-based Epoxy Resin: Controllable Degradation, Chemical Recovery and Antimicrobial Property

Endowing epoxy resin derived from bio-based glycidyl ester with controllable degradation in mild condition and high-valued recovery is a huge challenge. We design a novel cross-linked network with the degradable spior acetal structure orderly distributed on branch chains through the curing reaction between camphoric acid-based diglycidyl ester and vanillin-based amine curing agent. To investigate degradation mechanism of the epoxy resins, the degradation behaviors in 0.1 mol/L H+ acidic aqueous solutions for 48 h at 50 degrees C were monitored by the degradation kinetics and real-time H-1-NMR spectra. The result indicated that the cross-linked network with spiro acetal structure was hydrolyzed into pentaerythritol and oligomers, and then camphoric acid was obtained by the hydrolyzation of ester bonds in oligomers. The degradation products in different periods were extracted by water to recover the raw material monomer (yield, pentaerythritol >85.5%, camphoric acid >58.9%), which realized the controllable degradation and chemical recovery of epoxy resin by a green method. The curing agent formulation of the epoxy resin was adjusted to enhance thermal stability and tensile properties of resin samples, and samples with NVP performed excellent antimicrobial property (ratio, >95%) for both E. coli and S. aureus bacteria because of beta-amino alcohols generated in the curing reaction. The above result will inspire more synthesis of epoxy resin with controllable degradation, chemical recovery and antimicrobial property.