Stability Of Polylactide Research Articles

Effect of an Antioxidant Based on Red Beetroot Extract on the Abiotic Stability of Polylactide and Polycaprolactone.

This study investigated the effect of natural antioxidants inherent to beetroot (Beta vulgaris var. Vulgaris) on the ageing of environmentally friendly plastics. Certain properties were examined in this context, comprising thermal, mechanical, and morphological properties. A visual evaluation of relevant changes in the given polymers (polylactide and polycaprolactone) was conducted during an ageing test in a UV chamber (45 °C, 70% humidity) for 720 h. The films were prepared by a casting process, in which samples with the extract of beetroot were additionally incorporated in a common filler (bentonite), this serving as a carrier for the extract. The results showed the effect of the incorporated antioxidant, which was added to stabilize the biodegradable films. Its efficiency during the ageing test in the polymers tended to exceed or be comparable to that of the reference sample.

Stability of polylactide as potential packaging material in solutions of selected surfactants used in cosmetic formulae

Currently the use of different types of cosmetics is an integral part of our life. For this reason the stability of packaging materials in contact with popular cosmetic ingredients is crucial. In this work a study on the properties of polylactide (PLA) as potential packaging in selected surfactant solutions (sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES)) has been carried out. For referential purposes immersion in distilled water has also been conducted. After previously established time, the difference in mass of polymer films as well as in the average molecular weight of PLA has been measured. Moreover the changes in surface morphology and in thermal parameters of PLA have been studied. The results indicate that the most significant changes in the properties of the PLA as well as in pH of the studied mediums have been observed in the case of storage in SLES solution. This phenomenon occurs because the sodium laureth sulfate is responsible for the increase in acidity, resulting from the SLES self-hydrolysis. Obtained result can be useful for industry in order to protect cosmetic products and consumers.

Poly(1-butene) as a modifier of polylactide properties

This work investigates the effects of semicrystaline poly(1-butene) on amorphous polylactide in relation to mechanical, thermal and rheological properties. The blends were prepared by melt mixing, and poly(1-butene) content ranged from 5 to 40 wt %. It was found that 5 wt % poly(1-butene) heightened impact strength by more than double, however, other mechanical properties decreased. Poly(1-butene) significantly affected the glass transition temperature of polylactide, while the melting temperature of blends with 5 and 15 wt % poly(1-butene) slightly decreased. Thermogravimetric measurements revealed that the thermal stability of polylactide improved if poly(1-butene) was present, and rheological properties exhibited enhanced complex viscosity in combination with dynamic moduli.

From Nutraceutics to Materials: Effect of Resveratrol on the Stability of Polylactide

Resveratrol is a naturally occurring polyphenol, well known as a nutritional supplement due to its strong antioxidant properties associated with anti-inflammatory activity and possible prevention of cardiovascular diseases. In this work, the effect of resveratrol on thermal, thermo-oxidative, and photo-oxidative degradation of polylactide is reported in the frame of developing fully biobased polymer formulations. Characterization of PLA films by thermal methods and photo-oxidative treatments demonstrated that resveratrol catalyzed high temperature transesterification reactions under inert atmosphere, whereas it efficiently inhibited the exothermal oxidative reactions of the polymer backbone. Low-temperature photochemical degradation experiments on PLA films allowed elucidating the stabilization mechanisms of the phenolic additive. Resveratrol is capable of slowing the oxidative chain reaction of PLA through a peroxyl radicals scavenging mechanism, while it has little effect on the direct photolytical cleavage of the ester bonds. Moreover, direct resveratrol oxidation as well as the reaction between the phenol and photo-oxidized polymer species yield secondary photoproducts, which are also able to protect PLA against photo-oxidation likely due to the UV screening effect of the formed chromophores. Resveratrol is thus proposed as an eco-friendly and biocompatible additive for a sustainable approach to the stabilization of PLA films in packaging and other applications.

Sterility, mechanical properties, and molecular stability of polylactide internal‐fixation devices treated with low‐temperature plasmas

Sterility, mechanical properties, and molecular stability of polylactide internal‐fixation devices treated with low‐temperature plasmas