Towards Controlled Degradation of Poly(lactic) Acid in Technical Applications

Abstract

Environmental issues urge for the substitution of petrochemical-based raw materials with more environmentally friendly sources. The biggest advantages of PLA over non-biodegradable plastics are that it can be produced from natural sources (e.g., corn or sugarcane), and at the end of its lifetime it can be returned to the soil by being composted with microorganisms. PLA can easily substitute petroleum-based plastics in a wide range of applications in many commodity products, such as disposable tableware, packaging, films, and agricultural twines, partially contributing to limiting plastic waste accumulation. Unfortunately, the complete replacement of fossil fuel-based plastics such as polyethylene (PE) or poly(ethylene terephthalate) (PET) by PLA is hindered by its higher cost, and, more importantly, slower degradation as compared to other degradable polymers. Thus, to make PLA more commercially attractive, ways to accelerate its degradation are actively sought. Many good reviews deal with PLA production, applications, and degradation but only in the medical or pharmaceutical field. In this respect, the present review will focus on controlled PLA degradation and biodegradation in technical applications. The work will include the main degradation mechanisms of PLA, such as its biodegradation in water, soil, and compost, in addition to thermal- and photo-degradation. The topic is of particular interest to academia and industry, mainly because the wider application of PLA is mostly dependent on discovering effective ways of accelerating its biodegradation rate at the end of its service life without compromising its properties.

Natural Fiber-Reinforced Polylactic Acid, Polylactic Acid Blends and Their Composites for Advanced Applications

“…Urayama et al [ 66 ] discovered that after 20 months in soil, PLA plates decrease their molecular weight by 20%. According to Teixeira et al [ 67 ], the PLA degradation is affected not only by the characteristics of the specimen, such as degree of crystallinity, molecular weight, sample morphology, and molecular structures, but also by the surrounding environmental conditions. In addition, the surface of PLA is very permeable.…”

Pathways to Green Perspectives: Production and Characterization of Polylactide (PLA) Nanocomposites Filled with Superparamagnetic Magnetite Nanoparticles

“…PLA is produced from non-fossil renewable natural resources through the fermentation of polysaccharides or sugar, e.g., extracted from corn or sugar beet, and corresponding wastes, while the most relevant end-life scenario is related to its biodegradability under controlled industrial composting conditions [6] or in the natural environment [14,15] (e.g., at a lower rate in the soil). The life cycle of PLA demonstrates that this biopolyester is a performant and sustainable alternative to the petrochemical polymers with less greenhouse gas emissions, while at the end of its service life, it can be degraded to CO 2 and biomass, allowing for a reduction in landfill volumes, thus contributing to the so-called carbon sink [14]. Moreover, the biodegradability of PLA in conjunction with the utilization of selected disposal systems, such as composting and anaerobic digestion, offers an end-of-life solution to completely remove the plastic from the environment and to close the carbon cycle [6,14].…”

“…The life cycle of PLA demonstrates that this biopolyester is a performant and sustainable alternative to the petrochemical polymers with less greenhouse gas emissions, while at the end of its service life, it can be degraded to CO 2 and biomass, allowing for a reduction in landfill volumes, thus contributing to the so-called carbon sink [14]. Moreover, the biodegradability of PLA in conjunction with the utilization of selected disposal systems, such as composting and anaerobic digestion, offers an end-of-life solution to completely remove the plastic from the environment and to close the carbon cycle [6,14].…”

Specificities of Scanning Electron Microscopy and Histological Methods in Assessing Cell-Engineered Construct Effectiveness for the Recovery of Hyaline Cartilage

“…However, classical histological processing leads to partial degradation of the polymer carrier; therefore, the preparation and assessment of cryosections using fluorescence and confocal microscopy seems to be more suitable for effective data analysis. PLA hydrolyzes in the presence of many organic solvents (including xylene and 50% ethanol/water mix), which makes the polymer matrix swell, increasing chain mobility and rapid solvent-induced crystallization [ 31 , 32 ]. SEM is another method for assessing the regeneration of hyaline cartilage.…”