Shape memory behavior of the 100P-HDI foam samples is re-
ported in Fig. 5. The results obtained were similar to those ob-
tained in a previous study of related compositions [14], i.e. the
shape recovery was lower for initial cycles and was seen to im-
prove for successive cycles. Average shape recoveries of 91 ± 3,
94 ± 1, 96 ± 1, 98 ± 1 and 99 ± 1%, respectively, were recorded for
the five consecutive cycles over five samples. The loss in shape
recovery in the initial few cycles is often attributed to macroscopic
changes in the material, such as damage to cell struts/membranes
[14]. However, on storage at T > T g (20 °C) for $24 h after the cyclic
testing, the samples showed a consistent recovery to 98–99% of
their original dimensions. Hence a significant part of the otherwise
minor loss in recovery in the initial cycles was eventually
recovered.