To analyze the behavior of the crystals in this type of polymers, the WAXS and DSC techniques are used; these techniques help to determine what percentage of the polymer are crystals and how they are organized. This is due to the fact that the crystallinity decreases as the crosslinking increases, since the chains lose the ability to arrange themselves and order is essential to achieve crystallinity.
A second problem present when crosslinking molecules is melting, since an excess of crosslinking modifies the molecule in such a way that it stops melting (similar to a thermoset) and therefore the temporary shape cannot be obtained.
The control of curing either by electromagnetic waves or with peroxides is very important since it increases the T and decreases the crystallinity, determining factors in the shape-shape-memory effect.
In the case of biocompatible semicrystalline systems such as poly(ε-caprolactone) and poly(n-butyl acrylate), crosslinked by photopolymerization it has been reported that the crystallization behavior is affected by the cooling rate, as in any other semicrystalline polymer, but the heat of crystallization remains independent of the cooling rate.
The influence of the crosslinking of the molecules, the cooling rate and the crystallization behavior are specific to each system and impossible to enumerate since the synthesis possibilities are almost infinite.
Crystallizable polymers such as oligo(ε-caprolactone) can have amorphous segments such as poly(n-butyl acrylate) and the molecular mass ratio of each determine the behavior of the system in programming temporary form and recovery to permanent form.