Dual-catalyst effect on the molecular weight enhancement of polyfurfuryl alcohol resin and stability

This study advances furan chemistry by synthesising high-molecular-weight polyfurfuryl alcohol (PFA) resin (Mw = 118,959 g/mol) from furfuryl alcohol (FA) using a co-catalytic system, compared to conventional single-catalytic methods. Unlike traditional single-catalyst approaches, our method significantly increases the molecular weight of the resulting PFA, as confirmed by gel permeation chromatography (GPC), which shows a molecular weight increase of up to 60%. The dual-catalyst system also enhances the thermal stability of the resin, with thermogravimetric analysis (TGA) revealing a higher decomposition temperature (over 100 °C) compared to PFA synthesised using a single catalyst. Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy further corroborate the structural integrity and successful polymerisation of furfuryl alcohol under these conditions. The co-catalytic approach uses acetic acid as the catalytic precursor and hydrochloric acid (HCl) as the primary catalyst, allowing controlled polymerisation and achieving higher molecular weight while maintaining processability. Comprehensive characterisation reveals that the resulting PFA resin has a highly irregular chain structure with increased chain packing, enhancing its properties. The synthesised PFA shows excellent shelf life, remaining stable for over six months without forming a hard, insoluble solid when stored at room temperature. The higher molecular weight significantly improves the PFA resin’s mechanical properties, thermal stability, and chemical resistance, making it suitable for standalone moulded materials, composites, coatings, adhesives, and nanostructured carbons. The co-catalytic system elevates molecular weight and simplifies the synthesis process, making it more practical and reproducible. By leveraging furans' unique properties, this study opens new avenues for developing polymeric systems with superior attributes, contributing to sustainability and defossilisation in material science.