Page 158 - Biodegradable Polyesters

136 6 Shape Memory Systems with Biodegradable Polyesters

Cooling under
fixed strain

D C
Recovery
Deformation

Heating
(a)
A B

D′
Cooling under
fixed stress

Recovery
D

C

Deformation

Heating
(b)
A B

Figure 6.2 Schematic representation of domains. During heating T m and upon cool-
the structural evolution in sol–gel cross- ing T were surpassed, and recovery took
c
linked PCLduringone-(a) andtwo-way (b) place above T .Both T m and T rose with
m
c
SM cycles. Note: filled gray circles repre- the cross-linking density of PCL. (Ref. [14],
sent the sol–gel induced cross-links, while reprinted with permission of Elsevier.)
black domains mark the crystalline PCL