Plastic Waste and Recycling
Chapter 5 - Biodegradable plastics
Abstract
The concept of materials coming from nature with environmental advantages of being biodegradable is very attractive to industry and to consumers. Biodegradable plastics are often perceived as the possible solution for the waste problem, but biodegradability is just an additional feature of the material to be exploited at the end of its life in specific terms related to the disposal environment and the time for degradation, which is often forgotten. Biodegradability should be considered as a favored choice for the applications that demand a cheap way to dispose of an item after it has fulfilled its role (e.g., for food packaging, agriculture, or medical products).
References (0)
Cited by (72)
Design and development of dual drug-loaded nanofibrous inserts for ophthalmic sustained delivery of AMK and VAN: Pharmacokinetic study in rabbit's eye
2024, International Journal of PharmaceuticsBacterial corneal keratitis is a damage to the corneal tissue that if not treated, can cause various complications like severe vision loss or even blindness. Combination therapy with two antibiotics which are effective against Gram-positive and Gram-negative bacteria offers sufficient broad-spectrum antibiotic coverage for the treatment of keratitis. Nanofibers can be a potential carrier in dual drug delivery due to their structural characteristics, specific surface area and high porosity. In order to achieve a sustained delivery of amikacin (AMK) and vancomycin (VAN), the current study designed, assessed, and compared nanofibrous inserts utilizing polyvinyl alcohol (PVA) and polycaprolactone (PCL) as biocompatible polymers. Electrospinning method was utilized to prepare two different formulations, PVA-VAN/AMK and PCL/PVA-VAN/AMK, with 351.8 ± 53.59 nm and 383.85 ± 49 nm diameters, respectively. The nanofibers were simply inserted in the cul-de-sac as a noninvasive approach for in vivo studies. The data obtained from the physicochemical and mechanical properties studies confirmed the suitability of the formulations. Antimicrobial investigations showed the antibacterial properties of synthesized nanofibers against Staphylococcus aureus and Pseudomonas aeruginosa. Both in vitro and animal studies demonstrated sustained drug release of the prepared nanofibers for 120 h. Based on the in vivo findings, the prepared nanofibers' AUC0-120 was found to be 20 to 31 times greater than the VAN and AMK solutions. Considering the results, the nanofibrous inserts can be utilized as an effective and safe system in drug delivery.
Influence of the polymer type of a microplastic challenge on the reaction of murine cells
2024, Journal of Hazardous MaterialsDue to global pollution derived from plastic waste, the research on microplastics is of increasing public interest. Until now, most studies addressing the effect of microplastic particles on vertebrate cells have primarily utilized polystyrene particles (PS). Other studies on polymer microparticles made, e.g., of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), or poly (ethylene terephthalate) (PET), cannot easily be directly compared to these PS studies, since the used microparticles differ widely in size and surface features. Here, effects caused by pristine microparticles of a narrow size range between 1 - 4 µm from selected conventional polymers including PS, PE, and PVC, were compared to those of particles made of polymers derived from biological sources like polylactic acid (PLA), and cellulose acetate (CA). The microparticles were used to investigate cellular uptake and assess cytotoxic effects on murine macrophages and epithelial cells. Despite differences in the particles' properties (e.g. ζ-potential and surface morphology), macrophages were able to ingest all tested particles, whereas epithelial cells ingested only the PS-based particles, which had a strong negative ζ-potential. Most importantly, none of the used model polymer particles exhibited significant short-time cytotoxicity, although the general effect of environmentally relevant microplastic particles on organisms requires further investigation.
A review on fate and ecotoxicity of biodegradable microplastics in aquatic system: Are biodegradable plastics truly safe for the environment?
2024, Environmental PollutionPlastic products are extensively used worldwide, but inadequate management of plastic waste results in significant plastic pollution. Biodegradable plastic (BPs) offers an alternative to traditional plastics, however, not all BPs can fully degrade under natural conditions. Instead, they may deteriorate into biodegradable microplastic (BMPs) at a faster rate than conventional plastic, thereby posing an additional hazard to aquatic environments. This study provides a comprehensive overview of the fate of BPs in aquatic systems and their eco-toxicological effects on aquatic organisms such as algae, invertebrates, and fish. The findings highlight that BMPs have comparable or heightened effects compared to conventional microplastics (MPs) which physiochemical characteristic of the polymer itself or by the chemical leached from the polymeric matrix can affect aquatic organisms. While BPs is not a flawless solution to address plastic pollution, future research should prioritize investigating their production, environmental behavior, ecological impact, and whether BMPs inflict greater harm than conventional MPs.
Recent research advances on polysaccharide-, peptide-, and protein-based hemostatic materials: A review
2024, International Journal of Biological MacromoleculesHemorrhage is a potentially life-threatening emergency that can occur at any time or place. Whether traumatic, congenital, surgical, disease-related, or drug-induced, bleeding can lead to severe complications or death. Therefore, the development of efficient hemostatic materials is critical. However, the results and prognosis demonstrated by clinical means of hemostasis do not reach expectations. With the development of technology, novel hemostatic materials have been developed from polysaccharides (chitosan, hyaluronic acid, alginate, cellulose, cyclodextrins, starch, dextran, and carrageenan), peptides (self-assembling peptides), and proteins (silk fibroin, collagen, gelatin, keratin, and thrombin). These new materials exhibit high hemostatic efficacy due to the enhancement or interaction of various hemostatic mechanisms. The main forms include adhesives, sealants, bandages, hemostatic powders, and hemostatic sponges. This article introduces the clotting process and principles of hemostatic methods and reviews the research on polysaccharide-, peptide-, and protein-based hemostatic materials in the last five years. The design ideas and hemostatic principles of polysaccharide-, peptide-, and protein-based hemostatic materials are mainly introduced. Finally, we summarize material designs, advantages, disadvantages, and challenges regarding hemostatic materials.
Starch biocomposites preparation by incorporating organosolv lignins from potato crop residues
2024, International Journal of Biological MacromoleculesPlastic wastes accumulated due to food packaging pose environmental threats. This study proposes biopolymeric films containing lignins extracted from potato crop residues (PCR) through organosolv treatment as a green alternative to non-degradable food packaging. The isolation process yielded 43.9 wt% lignins with a recovery rate of 73.5 wt% achieved under optimum conditions at 180 °C with 50 % v/v ethanol. The extracted lignins were then incorporated into a starch matrix to create biocomposite films. ATR-FTIR analysis confirmed interactions between the starch matrix and extracted lignins, and XRD analysis showed the amorphous structure of lignins, reducing film crystallinity. The addition of 1 wt% of extracted lignins resulted in a 87 % reduction in oxygen permeability, a 25 % increase in the thermal stability of the film, and a 78 % enhancement in antioxidant. Furthermore, introducing 3 wt% lignins led to the lowest water vapor transmission rate, measuring 9.3 × 10−7 kg/s·m2. Morphological studies of the films demonstrated a homogeneous and continuous structure on both the surface and cross-sectional areas when the lignins content was below 7 wt%. These findings highlight the potential of using organosolv lignins derived from potato crop residues as a promising additive for developing eco-friendly films designed for sustainable food packaging.
Degradation of biodegradable plastics in waste management systems and the open environment: A critical review
2024, Journal of Cleaner ProductionDecades of extensive and exponentially growing production and use of conventional plastics have led to the accumulation of plastic waste in the environment, contributing to the anthropocene pressure on ecosystems. Bioplastics (defined as bio-based and/or biodegradable plastics) have been promoted as a more sustainable alternative and substitute for conventional plastics. Nonetheless, the literature contains numerous conflicting conclusions regarding their suitability and environmental implications. One central point of contention concerns their biodegradability and the conditions necessary for proper degradation. In real-world settings, like anaerobic digestion plants or marine environments, biodegradable plastics may not degrade as rapidly or efficiently as suggested by laboratory tests. A systematic literature review was conducted to explore the current level of knowledge regarding the environmental fate and consequences of biodegradable plastics, thereby substantiating discussions on their future role in society. The review covered the degradation of biodegradable plastics in waste management environments (e.g., compost, sludge, or landfill) and the open environment (e.g., seawater, freshwater, or soil). As clearly highlighted by this review, comparisons and quantitative analysis of data on plastic degradation are challenged by significant methodological variations, encompassing differences in testing methods, test materials, and quantification strategies. Moreover, the review revealed several research gaps, highlighting, in particular, the need to i) intensify the research on polyhydroxyalkanoates (PHAs), polybutylene adipate terephthalate (PBAT), and polybutylene succinate (PBS) to match the level of polylactic acid (PLA) and starch-based plastics, ii) develop standard test methods in field conditions, and iii) couple degradation testing with ecotoxicological tests. The overview established in this review is essential for a more thorough evaluation of the environmental performance of biodegradable plastics. Furthermore, the findings of this study contribute to supporting the responsible future production and use of biodegradable plastics in various products, including assessing their role as alternatives to conventional plastics.