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 0-20wt%. The results revealed that the storage modulus at room temperature increased with increasing silicon carbide whisker, that is, from 5.1GPa (without silicon carbide whisker) to 8.8GPa (at 20wt%). Glass transition temperatures were increased with increasing silicon carbide whisker in the range of 154 degrees C-170 degrees C. Furthermore, all samples exhibited approximately 99% of shape fixity with recovery time ranging from 8 to 27min. Interestingly, the incorporation of silicon carbide whisker could significantly increase recovery stress from 3.4MPa (without silicon carbide whisker) to 11.2MPa (at 20wt%). 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 3-5min. These results suggest potential use of the composites as microwave-responsive sensors and other shape memory devices.