Improvement in Crystallization, Thermal, and Mechanical Properties of Flexible Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) Bioplastic with Zinc Phenylphosphate.

Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-PEG-PLLA) shows promise for use in bioplastic applications due to its greater flexibility over PLLA. However, further research is needed to improve PLLA-PEG-PLLA's properties with appropriate fillers. This study employed zinc phenylphosphate (PPZn) as a multi-functional filler for PLLA-PEG-PLLA. The effects of PPZn addition on PLLA-PEG-PLLA characteristics, such as crystallization and thermal and mechanical properties, were investigated. There was good phase compatibility between the PPZn and PLLA-PEG-PLLA. The addition of PPZn improved PLLA-PEG-PLLA's crystallization properties, as evidenced by the disappearance of the cold crystallization temperature, an increase in the crystallinity, an increase in the crystallization temperature, and a decrease in the crystallization half-time. The PLLA-PEG-PLLA's thermal stability and heat resistance were enhanced by the addition of PPZn. The PPZn addition also enhanced the mechanical properties of the PLLA-PEG-PLLA, as demonstrated by the rise in ultimate tensile stress and Young's modulus. We can conclude that the PPZn has potential for use as a multi-functional filler for the PLLA-PEG-PLLA composite due to its nucleating-enhancing, thermal-stabilizing, and reinforcing ability.

Physicochemical properties of lignin nanoparticles from softwood and their potential application in sustainable pre-harvest bagging as transparent UV-shielding films.

Technical lignin can be mainly obtained as a waste by-product from pulp industry, and it exhibits unique properties including ultraviolet adsorption, biodegradable, antibacterial, and antioxidant which can be utilized for bioplastic applications. However, common limitations of technical lignin for plastic applications are compatibility mainly due to poor interfacial adhesion, relatively large particle size and impurity. In this study lignin nanoparticles from softwood (S-LNPs) were successfully produced through a continuous-green-scalable antisolvent precipitation and the suitability of S-LNPs for fabrication of bio-composite polybutylene succinate (PBS) films using conventional blown film extrusion was examined. The attained S-LNPs showed lower ash content, higher phenolic content and higher lignin content compared to pristine softwood kraft lignin (S-lignin). Rheological property including shear viscosity and melt-flow index was determined. The obtained PBS/S-LNP composite films showed improved tensile modulus, higher water vapor transmission rate and excellent UV-shielding ability compared to neat PBS and PBS/S-lignin films. Accelerated weathering testing was conducted to replicate outdoor conditions. Degradation indices including carbonyl, vinyl and hydroxyl of the weathered PBS/lignin composites were evaluated for photo-oxidative stability. The S-LNPs as multifunctional bio-additives in biodegradable composite film exhibited superior performances of transparency, UV-absorption and stiffness with high photo-oxidative stability suitable for outdoor applications.