Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000–50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

The sustained release of pharmaceutical substances remains the most convenient way of drug delivery. Hence, a great variety of reports can be traced in the open literature associated with drug delivery systems (DDS). Specifically, the use of microparticle systems has received special attention during the past two decades. Polymeric microparticles (MPs) are acknowledged as very prevalent carriers toward an enhanced bio-distribution and bioavailability of both hydrophilic and lipophilic drug substances. Poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and their copolymers are among the most frequently used biodegradable polymers for encapsulated drugs. This review describes the current state-of-the-art research in the study of poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles and PLA-copolymers with other aliphatic acids as drug delivery devices for increasing the efficiency of drug delivery, enhancing the release profile, and drug targeting of active pharmaceutical ingredients (API). Potential advances in generics and the constant discovery of therapeutic peptides will hopefully promote the success of microsphere technology.

The objective of this study is to investigate the performance of the ultrafiltration process as a purification method on the dyeing properties of a newly synthesized homobifunctional reactive dye. This is a green–blue reactive dye with two vinylsulfone groups. Namely, several properties, such as exhaustion, substantivity, fixation, time to half dyeing, migration index, light fastness, and the effect of metal salts, were studied thoroughly. It was proven that the processed bifunctional reactive dye shows higher exhaustion, substantivity, and dye-uptake values than the untreated one. It was found that the dye fixation is higher for the ultrafiltrated (92%) compared to the non-ultrafiltrated (85%) dye, while the migration index is slightly lower. It is indicated that, due to the possible chemical affinity between the dye and the substrate, a stronger retention is noticed for the treated dye. All in all, high fixation and substantivity lead to higher dye valorization and result in less hydrolyzed waste dyestuff, leading to less water and organic liquid waste at an industrial scale. The effect of metal salts addition (Fe³⁺, Co²⁺ and Cu²⁺) was studied as well, for comparison reasons, but it was found to be unnecessary. It is proven by the property values calculated that the overall process is valuable, since lower dyebath concentrations are required for satisfactory results. Thus, in large-scale dyeings, the ultrafiltration process can be proven to be valuable for environmental protection reasons.