Moisture effects on dielectric relaxations of poly (ɛ-caprolactone)/starch biodegradable blends: Local, interfacial and segmental.

Poly(ɛ-caprolactone)/starch biocomposites in a wide composition range were studied by thermally stimulated depolarization currents, TSDC, during the drying process following the effect on the dielectric relaxations of moisture loss and blend composition. PCL's cooperative chain mobility is unaffected by the presence of water which is mainly located in the starch inclusions as its segmental relaxation is fixed at 207K. The heterogeneities found in the amorphous phase of neat starch are also observed here as a bimodal α relaxation which shifts to higher temperatures as it dries.

Characterization of esterified cassava starch with long alkyl side chains and different substitution degrees.

The present work describes the characterization and thermal properties of hydrophobic starch obtained by the esterification of cassava starch with acyl imidazoles, acid chlorides and methyl ester derivatives of fatty acids with n-alkyl chains with 12-22 carbon atoms, in order to compare the dependence of their properties as a function of the length of the side chain and the methodology used for their synthesis. The n-acyl starches presented degrees of substitution (DS) between 0.06 and 1.