Melt Viscoelastic Assessment of Poly(Lactic Acid) Composting: Influence of UV Ageing.

This study is devoted to the degradation pathway (bio, photo degradation and photo/bio) of Poly(Lactic acid) PLA polymers by means of melt viscoelasticity. A comparison was made between three PLA polymers with different microstructures (L, D stereoisomers). Biodegradability was determined during composting by burying the polymer films in compost at 58 °C.

Identification of important abiotic and biotic factors in the biodegradation of poly(l-lactic acid).

The biodegradation of four poly(l-lactic acid) (PLA) samples with molecular weights (MW) ranging from approximately 34 to 160kgmol(-1) was investigated under composting conditions. The biodegradation rate decreased, and initial retardation was discernible in parallel with the increasing MW of the polymer. Furthermore, the specific surface area of the polymer sample was identified as the important factor accelerating biodegradation.

Photostability and photobactericidal properties of porphyrin-layered double hydroxide-polyurethane composite films.

The photostability and photobactericidal properties of PdTPPC (Pd(ii)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin)-ZnAl/PU (polyurethane) composite films have been studied in order to investigate their applicability as new photodynamic surfaces. These films comprise a PdTPPC porphyrin photosensitizer intercalated between the lamella of ZnAl layered double hydroxide and dispersed (1 wt%) into a polyurethane matrix. The study of the photophysical behaviour shows that the ZnAl LDH host enhances the chemical stability of the PdTPPC guest by minimizing photobleaching and quenching aggregation effects.

Preparation of microfibers from wood/ionic liquid solutions.

Two types of ionic liquids, 1-ethyl-3-methylimidazolim acetate and 1-ethyl-3-methylimidazolium lactate, were employed for the direct processing of pine wood into microfibers. The concentration of 5 wt.% of wood in ionic liquids was rated as the most appropriate for electrospinning.

Assessment of the interrelation between photooxidation and biodegradation of selected polyesters after artificial weathering.

Three commercially available biodegradable polymers, two different aromatic-aliphatic copolyesters and polylactic acid, intended for the fabrication of agricultural mulching films, in addition to other applications, were subjected to a series of tests with the aim of studying the relationship between their photooxidation and biodegradation. Photooxidation resulted in the rearrangement of polymeric chains, in the case of both copolyesters the events led to polymeric chain crosslinking and the formation of insoluble polymeric gel. The tendency was significantly more pronounced for the copolyester with the higher content of the aromatic constituent.

Strong interfacial attrition developed by oleate/layered double hydroxide nanoplatelets dispersed into poly(butylene succinate).

Poly(butylene succinate) (PBS) nanocomposite structure was studied as a function of the filler percentage loading. The resulting state of dispersion was evaluated by XRD and TEM, and the interfacial attrition between PBS chain and lamellar platelets by the melt rheological properties. Hybrid organic inorganic (O/I) layered double hydroxide (LDH) organo-modified by oleate anions was used as filler.