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.

In this work, poly(L-lactic acid)/thermoplastic alginate (PLA/TPA) biocomposites were prepared through a melt blending method. The TPA was initially prepared using glycerol as a plasticizer. The effects of TPA content on the interactions between blend components, thermal properties, phase morphology, mechanical properties, hydrophilicity, and biodegradation properties of biocomposites were systematically investigated. Fourier transform infrared (FTIR) spectroscopy analysis corroborated the interaction between the blend components. The addition of TPA enhanced the nucleating effect for PLA, as determined by differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) revealed poor phase compatibility between the PLA and TPA phases. The thermal stability and mechanical properties of the biocomposites decreased with the addition of TPA, as demonstrated by thermogravimetric analysis (TGA) and tensile tests, respectively. The hydrophilicity and soil burial degradation rate of biocomposites increased significantly as the TPA content increased. These results indicated that PLA/TPA biocomposites degraded faster than pure PLA, making them suitable for single-use packaging, but this necessitates careful optimization of TPA content to balance mechanical properties and soil burial degradation rate for practical single-use applications.

Lactic acid impregnated ground film paper was prepared using the method of lactic acid impregnation of raw paper. The physical properties, chemical composition, crystallinity, thermal stability, surface morphology of the paper, barrier properties, and light transmittance of the lactic acid paper were investigated using FT-IR, XRD, TGA, SEM, water vapor blocking, oxygen blocking, mechanical properties testing, and optical property testing. Results showed that at room temperature (20 degrees C), when lactic acid concentration was 100 %, reaction time was 48 h, and 100 degrees C high temperature drying prepared lactic acid paper, it exhibited superior performance: dry strength of 2.83 IkN/m, wet strength of 0.36 kN/m, Cobb value of 4.50 g/m2, tear of 359.42 mN, water vapor barrier of 693.46 g m-2 24 h-1, and oxygen barrier of 933.43 cm3 m-2 24 h-1. Degradation rate reached 22.94 % after two weeks of soil landfill.

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 study introduces biodegradable nursery bags using poly(lactic acid) (PLA), a widely used biodegradable polymer, and spent coffee grounds (SCGs), a byproduct of the brewing process in the coffee industry. SCGs were oil-extracted to produce extracted spent coffee grounds (exSCGs), which were characterized by their physical properties, chemical functionality, and thermal behavior. The exSCGs were blended with PLA at loadings of 5, 10, and 15 wt%. Analysis showed that exSCGs retained 3-5 wt% residual coffee oil, exhibiting a lower surface area (1.1163 m(2)/g) compared to SCGs (1.5010 m(2)/g), along with a higher pore volume (1.148 x 10(-3) cm(3)/g) and pore size (similar to 410 nm). All PLA/exSCG bio-composite films displayed a light brown color, well-dispersed exSCG particles, and excellent UV light barrier properties, with transmittance reduced to 1-2%. The residual coffee oil acted as a plasticizer, reducing the glass transition temperature, melting temperature, and crystallinity with increasing exSCG content. Mechanical testing revealed enhanced flexibility compared to neat PLA. Soil burial tests showed increased biodegradability with higher exSCG content, supported by SEM analysis revealing cracks around exSCG particles. The PLA/exSCG blend containing 10 wt% exSCGs exhibited optimal performance, with a significant increase in melt flow index (from 4.22 to 8.17 g/10 min) and approximately double the melt strength of neat PLA, balancing processability and mechanical properties. This innovation provides a sustainable alternative to plastic nursery bags, addressing waste valorization and promoting eco-friendly material development for agricultural applications.

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.

A multifunctional biodegradable additive powder has been created for simultaneous enhancement of toughness and compostability of the biopolymer poly(lactic acid) (PLA). PLA has promising strength and stiffness compared to commodity plastics, but the neat polymer is not a direct replacement for petroleum-based plastics in consumer products due to its brittle fracture and low ductility. Although officially certified as biodegradable, PLA suffers from a slow composting rate and is not considered compostable outside of specialized environments such as those found in industrial composters (where temperatures approaching 60 degrees C are used). A powder-based additive has been developed that increases both the elongation at break and the composting rate of PLA to enhance the attractiveness of PLA over current commodity plastics. In this study, various amounts of the additive are compounded into PLA using a single screw extruder. Test specimens are prepared using the additive manufacturing method of fused filament fabrication. The PLA-based composites show a minimal loss of strength and stiffness as compared to plasticized PLA resins, and the additives provide tunable properties to the material in the ability to control elongation versus strength and stiffness. Direct tensile testing of 3.75 mm filament for additive manufacturing to compare material properties is also investigated. The composting behavior is investigated using specimens made by extrusion as part of an additive manufacturing model system. Composting studies show an increase in composting rate under elevated temperature of 58 degrees C and 50 % relative humidity under modified ASTM D5338 soil contact testing. Microbial analysis indicates that the additive particles support the growth of specific degraders and shifts the composition of the microbial population of bacteria and fungi and has potential for enhancing the compostability in home compost.