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and organosilica are shifted to slightly higher temperatures however the starch and
organosilica largely behave as separate components in this minimally interacting
hybrid material. Finally the two intercrosslinked hybrid materials show the most
dramatic changes in their thermal behaviour. In the case of the intercrosslinked hy-
brid involving both aminosilica and aminostarch crosslinking with the epoxide, the
starch decomposition is shifted to 327 °C while the propyl chain degradation of the
organosilica component is broadened and shifted considerably to 431 °C. We expect
that this is due to the increased number of thermal relaxation avenues available for
the organosilica component through its close interaction with the larger organic
network. Finally, the starch crosslinked biohybrid demonstrates the most substantial
change in its thermal decomposition behaviour. The starch component and the or-
ganosilica component have almost entirely coalesced with a low temperature shoul-
der visible at 365 °C and a peak at 395 °C. This represents a significant thermal
stabilization of the starch component of between 70 to 85 °C above that of native
starch. The coalescence of the two thermal features is consistent with the extensive
chemical interaction found in this biohybrid where the starch is behaving as the only
crosslinking agent for the organosilica component. This significant change in the
decomposition temperature of the starch is consistent with the behaviour observed
for the water loss temperature in this starch-crosslinked hybrid material given the
extent of modification of the starch morphology in this hybrid.
7.4
Conclusions
Biosilicate hybrid materials using starch components are a convenient and effec-
tive approach to constructing durable materials while incorporating polysaccharides
derived from renewable resources. In our work we have focused on the combina-
tion of biopolymers and preformed organosilicate colloids synthesized using sol-gel
techniques. With these convenient and robust building blocks, we have been able
to fabricate a range of biohybrid materials with varying degrees of interaction be-
tween the components. The different chemical interactions between the components
results in significant changes to the physical properties of the materials as demon-
strated in our work by the changes in the water loss and thermal decomposition of
the hybrids.
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