The growing significance of biodegradable plastics for environmental protection underscores the need to enhance their performance of degradation in natural environments. This study prepared PLA/PVA blends with varying ratios to assess the impact of PVA on their thermal properties, mechanical properties, and degradation behavior. Results indicated that as the PVA content increased from 0 to 100%, both tensile and flexural strengths initially decreased before increasing. Furthermore, the decomposition temperature of the blends decreased by 18-35 degrees C as the PVA content increased. Specifically, pure PLA exhibited a thermal degradation temperature of 332 degrees C; while, the blend with 80% PVA showed a reduced temperature of 296 degrees C. Hydrolysis tests showed that weight loss increased significantly with higher PVA content, with the 20PLA/80PVA blend losing 78.9% of its weight after 30 days, compared to only 0.13% for pure PLA. The mechanical properties of the 20PLA/80PVA blend decreased by 98.31% in tensile strength and 79.19% in hardness after 30 days of hydrolysis, demonstrating accelerated degradation. Soil degradation tests further revealed that the 20PLA/80PVA blend lost over 85% of its weight within 20 days; while, pure PLA lost less than 1%. These results suggest that altering the PLA/PVA ratio can substantially enhance degradation rates, offering valuable insights for the development of efficient biodegradable plastics.

Biodegradable plastic is the preferred alternative to traditional plastic products due to its high degradability, decreased dependence on fossil sources, and decreased global pollution according to the accumulation of traditional plastic. In the current study, the optimization of biodegradable plastic synthesis was studied using biomass reinforcement materials. The reinforcement material is cellulose extracted from sawdust to prepare biodegradable plastic using the casting method. Response surface methodology using Box-Behnken Design is used to optimize the main parameters affecting the tensile strength and elongation at the break of the biodegradable plastic. These parameters are cellulose fiber addition, acetic acid addition, and the mass ratio of glycerol to starch. The maximum tensile strength and elongation were obtained at 4.45 MPa and 5.24%, respectively, using 5% cellulose fiber addition and 11.24% acetic acid addition with a 0.266 w/w glycerol to starch mass ratio. Various analyses were performed on the produced biodegradable plastic, including FTIR, SEM, and thermal stability. The biodegradability of the produced biodegradable plastic after immersing the soil for 10 days was about 90% higher than the traditional plastics. The produced biodegradable plastic has a moisture content of 4.41%, water absorption of 81.5%, water solubility of 24.6%, and alcohol solubility of 0%. According to these properties, the produced biodegradable plastic can be used in different industries as a good alternative to traditional plastics.

Soil microbiomes drive many soil processes and maintain the ecological functions of terrestrial ecosystems. Microplastics (MPs, size <5 mm) are pervasive emerging contaminants worldwide. However, how MPs affect soil microbial activity has not been well elucidated. This review article first highlights the effects of MPs on overall soil microbial activities represented by three soil enzymes, i.e., catalase, dehydrogenase, and fluorescein diacetate hydrolase (FDAse), and explores the underlying mechanisms and influencing factors. Abundant evidence confirms that MPs can change soil microbial activities. However, existing results vary greatly from inhibition to promotion and non-significance, depending on polymer type, degradability, dose, size, shape, additive, and aging degree of the target MPs, soil physicochemical and biological properties, and exposure conditions, such as exposure time, temperature, and agricultural practices (e.g., planting, fertilization, soil amendment, and pesticide application). MPs can directly affect microbial activities by acting as carbon sources, releasing additives and pollutants, and shaping microbial communities via plastisphere effects. Smaller MPs (e.g., nanoplastics, 1 to <1000 nm) can also damage microbial cells through penetration. Indirectly, MPs can change soil attributes, fertility, the toxicity of co-existing pollutants, and the performance of soil fauna and plants, thus regulating soil microbiomes and their activities. In conclusion, MPs can regulate soil microbial activities and consequently pose cascading consequences for ecosystem functioning.

This study investigates the incorporation of thermoplastic starch (TPS) into polybutylene adipate terephthalate (PBAT) to create biodegradable plastic wraps for pathological waste burial in soil. TPS is added to PBAT to enhance biodegradability, as PBAT alone degrades slowly. The research examines the mechanical properties, biodegradation, morphology, and swelling behaviour of the blends. Key tests include xenon arc light exposure for accelerated aging, a formalin swelling test for permeability, and soil degradation analysis for weight loss. Results show that adding TPS significantly reduces tensile strength (65.53%) and elongation at break (93.35%), but the material still effectively serves its purpose as a wrapping for pathological waste. Morphological analysis reveals phase separation, and UV exposure further decreases tensile strength by 27.6%. The highest TPS composition (30TPS/70PBAT) shows the fastest mechanical degradation, indicating accelerated biodegradation. Despite minimal formalin absorption (16% within 1 day), the blends prevent formalin leaching, making them suitable for pathological waste containment.

Straw return and plastic film mulching are two critical management measures that not only maintain high and stable crop yields, but also have a significant impact on the ecological environment. However, there is still a lack of research on the comprehensive effects of straw return and different film mulching treatments on the ecological environment. Thus, a 2-year field experiment was conducted and six treatments, which included two main treatments, namely straw return (SR) and non-straw return (NR), and three sub-treatments, namely no film mulching (CK), plastic film mulching (PM) and fully biodegradable film mulching (BM), were applied in a garlic cropping system. Based on the life cycle assessment method, six endpoint damage categories, resource consumption, global warming potential, environmental acidification, eutrophication, human health, and ecotoxicity, were assessed. Furthermore, we also evaluated the costs and economic benefits of the six treatments and optimized the treatment of used mulch and straw off-farm. The results indicated that the environmental impacts of the six endpoint damages in the garlic cropping system were ranked as ecotoxicity, eutrophication, environmental acidification, global warming potential, human health, and resource consumption. The SR-BM treatment had the lowest life cycle environmental impact composite index at 27.68 per unit area, followed by SR-PM at 27.75. All six endpoint damage categories for the PM and BM treatments were lower than the CK treatment per t of yield, with the SR-BM treatment being the most economically efficient, yielding at 3691.03 CNYt-1 and exceeding that of the SR-CK treatment by 7.26%. Fertilizer inputs were the primary contributor to resource consumption, global warming potential, environmental acidification, eutrophication, and ecotoxicity, accounting for about 72.80% of these five environmental impacts. Crop protection significantly affected human health, and garlic mulching helped minimize pesticide use, thereby reducing potential health impacts. Compared to straw incineration and waste mulch power generation, straw power generation and waste mulch recycling granulation offered positive environmental benefits and were more effective offset strategies. In conclusion, straw return with biodegradable mulch is a synergistic cultivation measure that offers both environmental and economic benefits. For straw return with plastic film mulch, environmental impacts can be reduced by waste mulch recycling granulation.

Biodegradable plastics (BPs) are known to decompose into micro-nano plastics (BMNPs) more readily than conventional plastics (CPs). Given the environmental risks posed by BMNPs in soil ecosystems, their impact has garnered increasing attention. However, research focusing on the toxic effects of BMNPs on soils remains relatively limited. The degradation process and duration of BMNPs in soil are influenced by numerous factors, which directly impact the toxic effects of BMNPs. This highlights the urgent need for further research. In this context, this review delineates the classification of BPs, investigates the degradation processes of BPs along with their influencing factors, summarizes the toxic effects on soil ecosystems, and explores the potential mechanisms that underlie these toxic effects. Finally, it provides an outlook on related research concerning BMNPs in soil. The results indicate that specific BMNPs release additives at a faster rate during decomposition, degradation, and aging, with certain compounds exhibiting increased bioavailability. Importantly, a substantial body of research has shown that BMNPs generally manifest more pronounced toxic effects in comparison to conventional micro-nano plastics (CMNPs). The toxic effects associated with BMNPs encompass a decline in soil quality and microbial biomass, disruption of nutrient cycling, inhibition of plant root growth, and negative impacts on invertebrate reproduction, survival, and fertilization rates. The rough and complex surfaces of BMNPs contribute to increased mechanical damage to tested organisms, enhance absorption by microorganisms, and disrupt normal physiological functions. Notably, the toxic effects of BMNPs on soil ecosystems are influenced by factors including concentration, type of BMNPs, exposure conditions, degradation products, and the nature of additives used. Therefore, it is crucial to standardize detection technologies and toxicity testing conditions for BMNPs. In conclusion, this review provides scientific evidence that supports effective prevention and management of BMNP pollution, assessment of its ecological risks, and governance of BMNPs-related products.

Plastic pollution is a consequential problem worldwide, prompting the widespread use of biodegradable plastics (BPs). However, not all BPs are completely degradable under natural conditions, but instead produce biodegradable microplastics (BMPs), release chemical additives, and absorb micropollutants, thus causing toxicity to living organisms in similar manners to conventional plastics (CPs). The new problems caused by biodegradable plastics cannot be ignored and requires a thorough comparison of the differences between conventional and biodegradable plastics and microplastics. This review comprehensively compares their environmental fates, such as biodegradation and micropollutant sorption, and ecotoxicity in soil and water environments. The results showed that it is difficult to determine the natural conditions required for the complete biodegradation of BPs. Some chemical additives in BPs differ from those in CPs and may pose new threats to ecosystems. Because of functional group differences, most BMPs had higher micropollutant sorption capacities than conventional microplastics (CMPs). The ecotoxicity comparison showed that BMPs had similar or even greater adverse effects than CMPs. This review highlights several knowledge gaps in this new field and suggests directions for future studies.

Bioplastics are biobased or biodegradable plastic synthesized from natural resources with similar features to conventional plastic and environmental sustainability. Seaweed species abundant in the coastal regions of Bangladesh are yet to be explored for developing biodegradable plastic to solve the plastic pollution problem. Semi-refined kappa carrageenan was extracted from Gracilaria sp. with Pressurized Hot Water Extraction (PHWE) and blended with sorbitol and polyethylene glycol 1540 in this study, respectively. The presence of carrageenan and other functional groups was confirmed with FTIR analysis. The bioplastic films showed over 90 % biodegradability after 16 days of soil burial test and 98 % water solubility after immersion for 16 days. Maximum 20 MPa tensile strength and 44 % elongation were observed from the bioplastic films. The polyethylene glycol 1540 blended films showed better physical and mechanical properties. SEM analysis was conducted to evaluate the influence of tensile strength and elongation on the surface integrity of the bioplastic films. The findings indicate that Gracilaria sp. found in the coastal regions of Bangladesh, can be a potential candidate for developing bioplastics for food packaging and many other applications.

Microplastics leaching from aging biodegradable plastics pose potential environmental threats. This study used response surface methodology (RSM) to investigate the impact of temperature, light, and humidity on the aging characteristics of polylactic acid (PLA). Key evaluation metrics included the C/O ratio, functional groups, crystallinity, surface topography, and mechanical properties. Humidity was discovered to have the greatest effect on the ageing of PLA, followed by light and temperature. The interactions between temperature and light, as well as humidity and sunlight, significantly impact the aging of PLA. XPS analysis revealed PLA underwent aging due to the cleavage of the ester bond (O-C=O), resulting in the addition of C=O and C-O. The aging process of PLA was characterized by alterations in surface morphology and augmentation in crystallinity, resulting in a decline in both tensile strength and elongation. These findings might offer insights into the aging behavior of degradable plastics under diverse environmental conditions.

Decades 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.