Biodegradable SMPUs have been developed by Knight et al. (16), who reported on POSS (polyhedral
oligosilsesquioxane)-based biodegradable SMPs exhibiting a well-defined Tg for poly(d,llactide)
soft segments and hard segments containing the POSS moiety. Excellent phase separation
was observed with a sharp soft-segment Tg largely independent of POSS loading in the hardsegment
phase. Also observed was an increase in latent heat of melting of the hard-segment phase
from 0.35 to 1.5 J g−1 with increasing POSS loading at a relatively constant Tm of 115◦C. Consequently,
the rubber elastic plateau increased in flatness and breadth with POSS hard-block content.
TheSMperformances included near-perfect fixing (>99%) and strain recovery that increased with
each cycle: 71%, 89%, and 93% for the first through third cycles for a tensile strain of 30%. The
materials were proven to be biodegradable, opening the potential for resorbable medical implants
with SM characteristics.