Rapid rate of fossil fuels consumption has led to their limited availability and has caused air pollution, global warming, and other environmental issues. The current research is therefore increasingly focused on seeking polymers from renewable resources that could replace petroleum-based materials. Bio-based benzoxazines can also be obtained from natural raw materials, which, due to their chemically crosslinked structure, have great potential as shape memory polymers (SMP). These have opened up opportunities for new areas of application over the last two decades.
In experimental work, benzoxazine monomer based on diphenolic acid and stearylamine and based on diphenolic acid and Jeffamine D-2000 was synthesized. Their chemical structures have been confirmed by infrared spectroscopy (IR). To investigate the effect of benzoxazine copolymer from biorenewable sources on shape memory, benzoxazine copolymer with the ring-opening polymerization at high temperature in various weight ratios was prepared. Thermal properties of the cross-linked samples were studied with differential scanning calorimetry (DSC), which provided necessary data for further studying of the shape memory effect. In addition to DSC analysis, the success of cross-linking was also studied with IR. The cyclic bending tests were employed to evaluate potential applicability and efficacy of the shape memory properties. With tests, the shape memory was confirmed and evaluated with shape fixity ratio (Rf) and shape recovery ratio (Rr). The samples have thus achieved a fairly good shape fixity ratio (37–95 %) at room temperature and a high shape recovery ratio (87–100 %) at 10 C above the glass transition temperature in the first cycle after 30 minutes. Good balance between shape memory performances and thermal properties showed a copolymer with a weight ratio of 50 : 50, as samples with increasing stearylamine content better retained shape, and samples with increasing Jeffamine D-2000 content better restored shape. It was also observed that samples undergo at least 4 shape memory cycles.