Abstract
Formaldehyde used in manufacture and curing of phenol formaldehyde (PF) resins is a big challenge for the PF industry with respect to sustainability and human health. Glucose has grand potential to replace formaldehyde in synthesis of bio-based phenolic novolac resins curable with hexamethylenetetramine (HMTA, derived from formaldehyde), an obstacle to achieve formaldehyde-free curing. This study reports the curing of phenol-glucose novolac resin with a bis-phenol-A type epoxy without using HMTA. The curing process was investigated by using dynamic differential scanning calorimetry measurements at different heating rates. Apparent activation energy of the curing reaction is 109.6 kJ/mol. Sestak-Berggren equation model was determined to be the reaction model according to Malek methods. The model-predicted reaction rates showed a good agreement with the experimental results. The results showed that the curing process was complicated; the kinetics expression was shown to be first-order autocatalytic reaction.