(291e) Synthesis and Curing of Phenol- 5-(Hydroxymethyl)Furfural (PHMF) Novolac Resin and Its Formaldehyde-Free Curing With Organosolv/Kraft Lignin (OSL/KL)

The use of formaldehyde to prepare phenol-formaldehyde (PF) resins is one of the primary challenges for the world-wide PF industry with respect to both sustainability and human being health. Lignocellulosic biomass has tremendous potential as a feedstock to make renewable polymers. This study reports the synthesis of novel glucose-based PHMF resin and its curing reaction with OSL/KL to produce formaldehyde-free phenolic resins. The use of HMF which was converted from glucose allows an economical and green route to synthesize phenolic resin without formaldehyde consumed or released and enhances its reactivity towards phenol. The chemical structure of PHMF was characterized by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (¹H NMR). Polymer molecular weight was determined by Gel permeation chromatography (GPC). OSL/KL, which are rich in woody biomass, were proven to be environmentally benign curing agents for PHMF. The curing mechanism was studied by carbon NMR (¹³C NMR), which demonstrated the occurrence of alkylation reaction between lignin's hydroxylmethylene group and PHMF’s para- carbon of phenolic hydroxyl group. Further studies regarding curing kinetics were conducted by using dynamic differential scanning calorimetry (DSC) and isoconversional methods to find out kinetic parameters. For the purpose of its application as replacement of PF resin, performances of OSL/KL cured PHMF were tested in terms of thermal stability, and mechanical properties. This research project realized curing of phenolic resin with OSL/KL for the first time among open publications. The results obtained presented OSL/KL to be promising curing agents for PHMF and recent results presented here will help make eco-friendly phenolic adhesive a practical reality.