As the development of renewable materials has undergone a renaissance in recent decades, numerous biomass related resources have been utilized to replace or supplement the petroleum-based bisphenol A (BPA). Among these feedstocks, lignin is the most reasonable candidate for making epoxy thermosets since it is the sole large-volume sustainable source composed of an aromatic skeleton. As lignin is featured by methoxyaromatics connected by ether linkages, lignin-derived phenols typically contain methoxy groups that can affect the material properties, thermal stability and decomposition pathways of derivative thermosetting resins.
The first aim of this proposal is to prepare fully-biobased triphenylmethane-type polyphenols (TPs) with different number of methoxy groups. TP structure allows for a way of manipulating the number of methoxy. By controlling the starting aromatic aldehydes and phenols, TPs with 0 to 6 methoxys can be readily realized via acid-catalyzed condensation. To explore their potential as precursors to epoxy thermoset, the second aim of this proposal is to convert selected TPs to glycidyl ethers and cured with hardeners. Especially, effect of methoxy on thermal and mechanical properties (modulus, glass transition temperature, etc.) of lignin-derived epoxy thermosets will be investigated via thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA).
Advisor: Mahdi Abu-Omar