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

In this paper, the influence of the molecular structure of polylactide (PLA)—characterised by its molar mass and content of d-lactide isomer—on the molecular ordering and α’–α form transition during fibre manufacturing by the wet spinning method is described. Fibres were studied by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). Additionally, the physical and mechanical properties of the fibres were determined. This study also examines the preliminary molecular ordering and crystallisation of PLA fibres at various draw ratios. The performed experiments clearly show the dependence of the molecular ordering of PLA on the molar mass and d-lactide content during the wet spinning process. The fibres manufactured from PLA with the lowest content of d-lactide and the lowest molar mass were characterised by a higher tendency for crystallisation and a higher possibility to undergo the disorder-to-order phase transition (α’ to α form). The structural changes in PLA explain the observed changes in the physical and mechanical properties of the obtained fibres.

The application of biobased and biodegradable polymers, such as polylactide (PLA), in fused deposition modeling (FDM) 3D-printing technology creates a new prospect for rapid prototyping and other applications in the context of ecology. The popularity of the FDM method and its significance in material engineering not only creates new prospects for the development of technical sciences on an industrial scale, but also introduces new technologies into households. In this study, the kinetics of the hydrolytic degradation of samples obtained by the FDM method from commercially available PLA filaments under a thermally accelerated regime were analyzed. The investigation was conducted at the microstructural, supramolecular, and molecular levels by using methods such as micro-computed tomography (micro-CT), wide-angle X-ray diffraction (WAXD), viscosimetry, and mass erosion measurements. The obtained results clearly present the rapid structural changes in 3D-printed materials during degradation due to their amorphous initial structure. The complementary studies carried out at different scale levels allowed us to demonstrate the relationship between the observed structural changes in the samples and the hydrolytic decomposition of the polymer chains, which made it possible to scientifically understand the process and expand the knowledge on biodegradation.

In this study, differences in the kinetics of the thermal-supported hydrolytic degradation of polylactide (PLA) wet spinning fibres due to material variance in the initial molecular and supramolecular structure were analysed. The investigation was carried out at the microstructural and molecular levels by using readily available methods such as scanning electron microscopy, mass erosion measurement and estimation of intrinsic viscosity. The results show a varying degree of influence of the initial structure on the degradation rate of the studied PLA fibres. The experiment shows that hydrolytic degradation at a temperature close to the cold crystallization temperature is, on a macroscopic level, definitely more rapid for the amorphous material, while on a molecular scale it is similar to a semi-crystalline material. Furthermore, for the adopted degradation temperature of 90 °C, a marginal influence of the pH of the degradation medium on the degradation kinetics was also demonstrated.