Natural magnolol derivatives as platform chemicals for bio-based phthalonitrile thermoset: Achieving high performances without an external curing agent

Abstract Bio-based polymers with better comprehensive properties, showing more competitiveness than their petroleum-based counterparts in high-tech fields is an increasingly trend but also a formidable challenge. In the study, bio-based phthalonitrile precursors were synthesized from natural occurring magnolol derivatives through a highly efficient one step process. Self-curing reactions can proceeded with allyl groups in the resultant precursors without sacrificing the thermal stabilities of the thermoset resins. The curing behavior, mechanism and processability of the phthalonitrile precursors were studied, and the thermal stabilities of cured polymers were evaluated. Of the two bio-based precursors, the honokiol derivate exhibited a wide processing window of 163 °C with a point lower than 70 oC. After curing, both the magnolol- and honokiol- based resins showed glass transition temperature higher than 500 °C and 5% weight loss temperature as high as 527 oC: These properties were superior to those of the petroleum-based reference without allyl group. A model reaction, showed that the curing mechanism of allyl/phthalonitrile system here was considered to be free radical polymerization. The results demonstrate that sustainable magnolol derivatives can be employed as platform chemicals to impart excellent performances to the bio-based polymers for great promise in cutting-edge applications.