Shape memory polymer nanocomposites Original Research Article

The paper describes the fabrication and characterization of composites with a shape memory polymer matrix and SiC nanoparticulate reinforcements. Composites based on a SMP matrix are active materials capable of recovering relatively large mechanical strains due to the application of heat. The composites were synthesized from a commercial shape memory polymer resin system and particulate SiC with an average diameter of 300 nm. Composites with weight fractions of 10%, 20%, 30%, and 40% nanoparticulate SiC were fabricated by casting samples with sizes ranging from a few hundred microns to several millimeters. The former size scale is consistent with a microcasting process for manufacturing microelectomechanical systems. The micro-hardness and elastic modulus of the nanocomposites increased by approximately a factor of 3 with the addition of 40 wt% SiC into the base resin. Unconstrained strain recoverability of the nanocomposites was found to depend on the fraction of SiC. For 180° bend tests, the recoverability of the nanocomposites was perfect for SiC weight fractions below 40%. For 40 wt% SiC, permanent bend strains were discovered. Constrained bending recovery force in the nanocomposites was shown to increase by 50% with the addition of 20 wt% SiC.