Biocomposites from bamboo fibers and palm oil-based thermosets: Effects of natural phenolic cross-linkers

The development of highly biobased and robust thermosetting matrices using renewable feedstocks has become an interesting topic in the field of composites. A series of palm oil (PO)-based thermosets were prepared from a PO vinyl monomer and natural phenolic (NP) cross-linkers. The PO fatty acid-ethyl acrylamide (POFA-EA) was synthesized via a facile transesterification of PO with N-(2-hydroxyethyl)acrylamide (HEAA). NPs including eugenol, methyl gallate, and tannic acid were used to generate aromatic rings-containing cross-linkers via a solvent-free and ultrasonic-assisted esterification. The mechanical properties and processibility of the developed PO resins were closely associated with the chemical structures and unsaturation degrees of the incorporated NP cross-linkers. Besides, the thermosets were further used as the matrices for bamboo fibers-reinforced biocomposites. The resulting biocomposites showed comparable mechanical properties and T(g)s toward those of petroleum-based counterparts. The biocomposites are anticipated to be fully decomposed because the PO matrices could be degraded in a mild alkali condition. This study provides insights to develop high performance and recyclable PO-based thermosets and their biocomposites.