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The crystallinity of poly(L-lactic acid) was changed by thermal annealing and its effects on electrical conduction characteristics were studied. Low-crystallinity samples have a higher conductivity and a higher remaining charge quantity than high-crystallinity samples. The sample shows two thermally stimulated current (TSC) peaks at around T g and about 20 C higher than T g when its crystallinity is low, while it shows only the former TSC peak when its crystallinity is high. The TSC peak at around T g is attributable to the micro-Brownian motion that enables the orientation of dipoles in a direction perpendicular to the polymer main chain, whereas the high-temperature peak is attributable to the orientation and magnitude change of the end-to-end vector in the polymer main chain.

In this paper, the influence of the various degradation conditions, on the molecular and 19 supramolecular structure of polybutylene succinate (PBS) and polybutylene succinate adipate 20 (PBSA) copolymer during degradation time is described. Experiment was carried out by the use 21 injection molded samples and normalized conditions of biodegradation in soil, composting and 22 artificial weathering. Materials were studied by using size-exclusion chromatography (SEC) 23 coupled with multiangle laser light scattering (MALLS) detection and wide-angle X-ray diffraction 24 (WAXD). Additionally, the physical and mechanical properties of the samples were determined. 25 The performed experiments clearly show difference impact of selected degradation condition on 26 the macroscopic, supramolecular and molecular parameters of studied aliphatic polyesters. The 27 structural changes in PBS and PBSA explain the observed changes in the physical and mechanical 28 properties of the obtained injection molded samples. 29

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Poly(lactide) (PLA) synthesized from starch is attracting much attention, since it is biodegradable and is able to attain a good mechanical property by a proper process such as stretching. It is known that the two PLA isomers, PLLA and PDLA, strongly interact with each other.Therefore, if the two isomers are blended, they form racemic crystals (stereocomplex). Since little is known about the effect of forming the stereocomplex on the dielectric properties, permittivity and thermally stimulated polarization current are compared among two kinds of PLLA films and a stereocomplex film. As a result, both the permittivity and current were found to become larger with a decrease in the crystallinity, irrespective of the crystal structure of the sample.