For the moment, shape memory polymers or SMPs are mainly used in aerospace and medicalapplication due to their limited mechanical properties, and small recovery speed andrecovery stress. The transformation and recovery speed is significantly affected by the heatingrate. One way to achieve a faster heating rate is by adding fillers; the SMP can be heated bydirect electrical resistivity, microwaves or induction. Adding carbon nanotubes or CNTs andcarbon black improves the heating rate when heating the SMPs by microwaves, but alsointroduced the occurrence of hot spots, limiting the usability of this method of heating. Addingup to 1.13% CNTs improved the electrical conductivity enough to allow direct electricalheating, greatly increasing the heating rate. When applying a fixed voltage to the samesample, both the evolution of the current and temperature differed during the first test fromthe following test runs, indicating alignment of the CNTs, resulting in a lower resistivity.
展开▼
