Having porous structure, large surface area, and high carbon content of biochar facilitates interface bonding of polylactic acid (PLA) composites, but uneven dispersion by its irregular morphology is becoming a new challenge in damaging properties. Based on this, the novelty of this study is using carbon quantum dots (CQDs) to overcome the performance defects of caused PLA composites by biochar while the ultimate goal is to reveal the influence mechanism of CQDs on structure, characteristics, and properties of PLA composites based on disclosing the forming mechanism of CQDs. It was found that adding CQDs accelerated the degradation of PLA from the results of Phosphate Buffer Saline (PBS) degradation, hydrolysis, and soil degradation. PLA/CQDs composite films also showed better thermal properties due to the excellent thermal stability of CQDs, and nucleation effect of CQDs should be responsible for the improvement of PLA crystallization. Additionally, having good activity, regular morphology, and uniform size of CQDs facilitated uniform dispersion and good interface combination in PLA system and thereby improved the tensile strength, tensile modulus, and elongation at break simultaneously. As a comparison, the tensile strength, tensile modulus, and elongation at break of 1 wt% PLA/CQDs composite films are 55.00 MPa, 1.76 GPa, and 9.84 %, this provides a promising, sustainable, and eco-friendly solution for reinforcing PLA composites.

The generation of polyethylene mulch film (PEMF) has promoted the rapid development of agriculture, while the non-degradability of it has caused the serious damage for the ecological environment. Currently, the biodegradable mulch film is considered as the most promising green substitutes for petroleum-based PEMF, owing to its environmental friendliness and biodegradability. Hence, this study fabricated a biodegradable mulch film (PSGA) through the crosslink (the esterification/amidation reactions and hydrogen bonds) between polylactic acid waste liquid (PLAWL) and sodium alginate (SA)/gum arabic (GA). Then attapulgite (ATP) was added to improve the mechanical properties. Therein, PLAWL was a kind of waste liquid from the fabrication process of polylactic acid (PLA) based on straw. At the same time, PSGA had similar insulation and water retention performance to PEMF and great UV resistance, thermal stability, and hydrophilicity surface. Additionally, pot experiment showed that PSGA could significantly promote the growth of Chinese white cabbage and the degradability ratio of that could reach 50% in a month. The total amounts of Rhizobiaceae (Ensifer and Allorhizobium-Neorhizobium-Pararhizobium, fixing free nitrogen gas and providing nitrogen nutrients for plants) in soil with PSGA was 12%, which was obviously higher than that in blank (4.5%). Therefore, this study provides a high-value recycling route for industrial waste liquid, offering an alternative solution to PEMF.

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.

Using Aloe Vera powder (AV) at varying concentrations - 1, 2, and 3% - polylactic acid/aloe vera (PLA/AV) composite films were prepared using the solvent casting process. All of the composites were exposed to 10, 25, and 40 kGy of electron beam (EB) radiation. It was examined how the thermal and mechanical characteristics of PLA/AV films were affected by electron beam radiation. XRD, FTIR, TGA, and biodegradation (soil burial) were used to analyze the irradiation films' characteristics. The findings showed that doses up to 25 kGy increased the neat PLA's tensile strength (TS). At lower doses up to 10 kGy, the addition of AV raises the TS values (particularly at 2% concentration). It appears adding varying proportions of AV powder enhances the thermal stability of PLA/AV composites. Biodegradability showed that films with AV were the most biodegradable, while those without AV were the least.

This article presents the development of laminate biocomposite via film stacking technique (FST) represents a method for processing fiber-reinforced thermoplastic laminate composites. The primary difficulty is the compatibility between the hydrophilic natural fibers and the hydrophobic PLA. With these limitations, the utilization of fiber content exceeding 50 wt% remains unfeasible. The PVA-based adhesives spraying technique is used to improve compatibility. Additionally, the effect of four different compatibilizer adhesives applied between the layers was examined: polyvinyl alcohol (PVA), PVA modified with 3-(trimethoxysilyl) propyl methacrylate (modified PVA), PVA-microfibrillated cellulose (PVA-MFC), and PVA-MFC modified with 3-(trimethoxysilyl) propyl methacrylate (modified PVA-MFC). The findings of the study demonstrate that the natural fibers/PLA laminate biocomposite comprises 65 wt% fiber and 35 wt% PLA, thus achieving successful preparation of laminate biocomposites containing over 50 wt% fibers using the FST technique. In comparison to PVA, modified PVA elevated the flexural strength of the laminate biocomposite by up to 122 %. The modified PVA-MFC compatibilizer, when compared with modified PVA, enhanced impact strength by up to 148 %, reduced surface polarity by 31 %, and notably improved thermal stability. In a QUV accelerated weathering test, all the laminates exhibited reduced flexural modulus and flexural strength, but the flexural strength of all the tested materials remained above 50 MPa. In soil burial tests, the PVA laminate exhibited the most rapid decomposition, whereas the modified PVA-MFC laminate demonstrated a notably slower degradation rate. Accelerated weathering notably increased the decomposition of the materials in soil. The modified PVA-MFC laminate emerged as the optimal material for producing a high-strength biodegradable laminate biocomposite, due to its superior mechanical and thermal properties, rendering them suitable for applications requiring structural support, such as interior construction, stage floors, furniture, and building interior decoration materials.

Many studies have reported the toxic effects of microplastics (MPs) on organisms, especially on how conventional plastics affect organisms after short-term exposure. The effects of biodegradable plastics on organisms are, however, largely unexplored, especially concerning their impact after long-term exposure. We perform a series of experiments to examine the effects of conventional (polyethylene (PE)) and biodegradable (polylactic acid (PLA)) microplastics on earthworms at three concentrations (0.5 %, 2 %, and 5 % (w/w)) and particle sizes (149, 28, and 13 mu m) over short- (14 d) and long-term (28 d) periods of exposure. Negative effects on earthworms are more pronounced following exposure to PE than PLA, particularly over the shorter term. After longerterm exposure, earthworms may adapt to PE and PLA environments. A close relationship exists between the effects of MPs on earthworms and activities of superoxide dismutase, catalase, and malondialdehyde enzymes, which we use to evaluate the degree of antioxidant damage. We report both PE and PLA to negatively affect earthworms, but for the effects of PLA to be less severe after longer-term exposure. Further investigation is required to more fully assess the potential negative effects of PLA use on soil organisms in agriculture.

Mulch films were fabricated from polylactic acid (PLA) with cellulose nanocrystals (PNC) extracted from pineapple leaves. The PNC was modified by incorporating 4 wt% triethoxyvinylsilane (TEVS), designated as 4PNC, to enhance its interaction with PLA. The films incorporated varying concentrations of PNC (1, 2, 4, and 8 wt%). The results indicated that higher PNC concentrations increased the water vapor permeability (WVP) and biodegradability of the composite films, while reducing light transmission. Films containing 4PNC, particularly at 4 wt % (PLA/4PNC-4), exhibited an 11.18 % increase in elongation at break compared to neat PLA films. Moreover, these films showed reduced light transmission, correlating with decreased weed growth, reduced WVP, and enhanced barrier properties, indicative of improved soil moisture retention. Additionally, PLA films with 4PNC demonstrated greater thermal degradation stability than those with unmodified PNC, suggesting enhanced heat resistance. However, there was no significant difference in aerobic biodegradation between the PLA films with PNC and those with 4PNC. This study confirms that TEVS-modified cellulose significantly enhances the properties of bio-composite films, making them more suitable for mulch film applications.

The improper disposal of plastics is a growing concern due to increasing global environmental problems such as the rise of CO2 emissions, diminishing petroleum sources, and pollution, which necessitates the research and development of biodegradable materials as an alternative to conventional packaging materials. The purpose of this research was to analyse the properties of biodegradable polymer blends of thermoplastic potato starch (TPS) and polylactide, (PLA) without and with the addition of citric acid (CA) as a potential compatibilizer and plasticizer. The prepared blends were subjected to a comprehensive physicochemical characterization, which included: FTIR-ATR spectroscopy, morphological analysis by scanning electron microscopy (SEM), determination of thermal and mechanical properties by differential scanning calorimetry (DSC), water vapour permeability (WVP), as well as biodegradation testing in soil. The obtained results indicate an improvement in adhesion between the TPS and PLA phases due to the addition of citric acid, better homogeneity of the structure, and greater compatibility of the polymer blends, leading to better thermal, mechanical and barrier properties of the studied biodegradable TPS/PLA polymer blends. After conducting the comprehensive research outlined in this paper, it has been determined that the addition of 5 wt.% of citric acid serves as an effective compatibilizer and plasticizer. This supplementation achieves an optimal equilibrium across thermal, mechanical, morphological, and barrier properties, while also promoting material sustainability through biodegradation. In conclusion, it can be stated that the use of thermoplastic starch in TPS/PLA blends accelerates the biodegradation of PLA as a slowly biodegradable polymer. While the addition of citric acid offers significant advantages for TPS/PLA blends, further research is needed to optimize the formulation and processing parameters to achieve the desired balance between mechanical strength, thermal and barrier properties and biodegradability.

The present work investigated the biodegradable polymer composite through the injection molding method. The matrix material of polylactic acid (PLA) and reinforcement particulates of novel Saccharum spontaneum (SS) were incorporated into the polymer matrix in the range of 5 % to 25 %. In addition to this study, Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD) were used to examine the structural and morphological analyses of a green polymer composite. Mechanical characteristics such as tensile strength, compressive strength, flexural strength, and shore D hardness have been studied. The soil degradation test and water absorption study were conducted as per the standards. The results showed that compared to pure PLA composite, the 25 wt. % SS-filled PLA composites showed better mechanical properties of tensile, flexural, compressive, and Shore D hardness at 87.41 MPa, 86.20 MPa, 86.4 MPa, and 91.4 SHN, respectively. Thus, the developed novel composite has a potential impact on low-speed applications. The excellent biodegradation property was confirmed with the help of a soil degradation test and water absorption study.