Recovery stress enhancement in shape memory composites from silicon carbide whisker–filled benzoxazine-epoxy polymer alloy

In this research, the benzoxazine-epoxy shape memory polymers with outstanding recovery stress improvement were prepared by filling with highly adamantine silicon carbide whisker at 0–20 wt%. The results revealed that the storage modulus at room temperature increased with increasing silicon carbide whisker, that is, from 5.1 GPa (without silicon carbide whisker) to 8.8 GPa (at 20 wt%). Glass transition temperatures were increased with increasing silicon carbide whisker in the range of 154°C–170°C. Furthermore, all samples exhibited approximately 99% of shape fixity with recovery time ranging from 8 to 27 min. Interestingly, the incorporation of silicon carbide whisker could significantly increase recovery stress from 3.4 MPa (without silicon carbide whisker) to 11.2 MPa (at 20 wt%). Moreover, the addition of silicon carbide whisker provides microwave actuating ability to the sample. Recovery time under microwave heating was significantly shortened to be in a range of 3–5 min. These results suggest potential use of the composites as microwave-responsive sensors and other shape memory devices.