There is currently a growing interest in biopolymers, such as bacterial cellulose and thermoplastic starch, which are renewable and abundantly available in nature. This study investigated the multilayer sandwich composite with thermoplastic starch and bacterial cellulose, using water (TPS/BC-w) and glycerol (TPS/BC-g) as coupling agents. The composites produced by compression molding resulted in a homogeneous, transparent and flexible structure. TPS/BC-w showed superior mechanical property and better adhesion compared to TPS/BC-g. Therefore, the permeability, biodegradation, hydrothermal aging and stability analyses were conducted only for TPS/ BC-w. The water vapor permeability of TPS/BC-w is 6.7 times lower than that of thermoplastic starch, indicating better barrier performance. Thermoplastic starch and bacterial cellulose degraded in about 9 days, and TPS/BCw degraded in 60 days. Biodegradation analysis by COQ release confirmed the complete biodegradation process, with COQ emissions of 57 %, 42.5 % and 39.6 % after 120 days for thermoplastic starch, bacterial cellulose and TPS/BC-w, respectively. TPS/BC-w remained intact for more than a year, in an environment without direct contact with soil or water. These results indicate that TPS/BC-w composed of natural macromolecules may exhibit functional properties and is useful for applications such as short-shelf-life packaging, particularly for dry products, due to its barrier properties and controlled biodegradability.

BackgroundUrea-based fertilizers are essential for agricultural productivity but contribute to environmental degradation by releasing soil nitrogen (N) through N leaching and runoff. To address these issues, this study develops and characterizes slow-release composites of thermoplastic starch (TPS) and epoxidized natural rubber (ENR) that incorporate 46-0-0 fertilizer. TPS, recognized for its moisture sensitivity and biodegradability, was blended with ENR to enhance matrix compatibility and optimize nutrient release from the fertilizer. The blending process included different fertilizer concentrations (6.9, 10, 15, and 20 wt%) within various components of the composite.ResultsThe characterization included evaluation of mechanical properties, water absorbance, biodegradability in soil, ammonium release, and ammonium leaching. The TPS/ENR composites exhibited a two-stage decomposition, with TPS dissolving first to provide an initial nutrient boost, followed by the biodegradation of ENR to ensure sustained nutrient delivery. Ammonium release assays demonstrated that TPS/ENR composites delayed nutrient dissolution compared to conventional fertilizers, significantly reducing nitrogen loss through leaching. Notably, the TPS/ENR composite with 6.9 wt% of 46-0-0 fertilizer exhibited the highest efficiency, achieving sustained ammonium release and enhancing soil nitrogen retention while mitigating phytotoxicity in lettuce and maize germination assays.ConclusionsThese findings highlight the potential and environmental benefits of delivering fertilizer in TPS/ENR composites to improve nitrogen fertilizer efficiency in agricultural systems. The slow-release mechanism provides both initial and sustained nutrient supply, addressing the dual challenges of early crop nutritional needs and long-term environmental sustainability.

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.

In municipal solid waste landfills (MSWL), the center and peripheral regions of the basal compacted clay liner (CCL) often experience steady elevated temperatures due to waste biodegradation and cyclic temperatures similar to the seasonal atmospheric temperature patterns, respectively. In the present study, the negative effects of cyclic elevated temperatures on the desiccation behaviour of a MSWL basal CCL was examined by subjecting CCL samples to multiple wet-dry cycles with different drying temperatures. It was observed that the extent of desiccation cracking experienced by the CCL rose as the drying temperature and number of wet-dry cycles increased. The present study also assessed the effect of different thermoplastic cooling pipes on the reduction of temperature rise and desiccation experienced by CCLs exposed to constant elevated temperatures (CETs). It was observed that the introduction of thermoplastic cooling pipes led to a significant attenuation of the final temperature (FT) and desiccation magnitude along the CCL depth in the face of all applied CETs, irrespective of the cooling pipe material employed. A comprehensively analysis of the final temperature distributions within the entire CCL, coolant and sand layer surrounding the cooling pipe was also carried out via the conduction of a numerical simulation. Overall, the present study revealed the adverse effects imposed by cyclic elevated temperatures on a CCL and the potential that thermoplastic cooling pipes possess to successfully reduce the temperature rise and desiccation experienced by a CCL in the face of different CETs.

In this work, environmentally friendly materials based on zein, glycerol, and xanthan gum (XG) are developed through the innovative use of extrusion and injection-molding methodologies for this type of bioplastic materials. This methodology has never been applied to thermoplastic zein materials and this approach represents a significant advancement over traditional cast film methods, enabling enhanced control over properties and expanding potential applications thanks to the possibility of producing new geometries. Mechanical properties show that XG increases the stiffness and hardness of the materials, achieving elastic modulus of 1294 MPa and tensile strengths of 21 MPa. The thermal stability of the formulations is also enhanced by the addition of XG, which considerably increases the maximum degradation rate temperature from 259 up to 340 degrees C. The wettability of the materials is assessed by contact angle measurements, which show a very high hydrophilicity (29 degrees), nonetheless, it was decreased to not so extremely low contact angle values thanks to the addition of XG (50 degrees), which is very positive from the point of view of food packaging applications. Finally, all materials proved to be completely disintegrated under controlled compost conditions after 9 weeks of incubation in controlled compost soil conditions, verifying the great environmentally friendly value of these formulations.

Developing biobased thermoplastic polyurethane (TPU) from renewable biomass resources is becoming urgent due to resource scarcity and environmental protection requirements. Herein, a chain extender diol (VAN-OH) containing dynamic imine bonds was synthesized using renewable biomass resource vanillin (VAN), then combined with 1,4-butanediol (BDO) in various proportions, and reacted with poly(caprolactone diol) and 4,4 '-diphenylmethane diisocyanate to synthesize degradable biobased TPU (BTPUs) with excellent performance. Fourier transform infrared, 1H NMR, X-ray diffraction, DMA, thermogravimetric analysis, molecular weight, chemical degradation, and mechanical tests systematically investigated the relationships between the polymer chain structure and the performance of BTPUs. The experimental results demonstrated that the high regularity and strong polar bonds (imine and ether) of VAN-OH enhanced the interactions between macromolecular chains and improved the hydrogen bonding combination, crystallinity, and phase separation of BTPUs, thereby exerting significant contributions to their thermomechanical and degradable properties. BVTPU1 with a mole ratio of BDO/VAN-OH = 7.5:2.5 exhibited the best mechanical performance, degradation time was 37.5% shorter, and initial pyrolysis temperature increased by 13.8% compared to BTPU0 without VAN-OH. In addition, BTPUs have shown some biodegradability and environmental friendliness in soil burial experiments under natural conditions.

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.

Developing bio-blends and biocomposites has become a widespread strategy to combat plastic pollution in line with sustainability principles and decarbonization necessities. Although chemically modified ternary and quaternary biocomposites are developing rapidly because of their broader processing and performance windows than single matrix and binary counterparts, a few have been reported about their biodegradation. Herein, diisocyanates-based chemically modified ternary biocomposites based on poly(butylene adipate-co-tere- phthalate), thermoplastic starch (TPS), poly(epsilon-caprolactone) (PCL), and cellulose (Mater-Bi/PCL/cellulose) are prepared and undergone soil burial biodegradation providing a broader perspective on biodegradation of complicated systems. The mass gain of sunflower sprouts, weight retention, and the appearance of biocomposites are studied and discussed in the course of biodegradation. The unfilled Mater-Bi/PCL bio-blends presented moderate mass loss over 12 weeks, attributed to the presence of TPS in the Mater-Bi phase. The PCL addition hindered TPS decomposition and featured a noticeably lower degradation rate compared to previous reports. A significant increase in the b* parameter (position on the blue-yellow axis in the CIELAB color space), along with the yellowness and whiteness indices, was observed. Prior to soil burial, roughness differences were negligible. Still, they significantly increased over time due to the higher hydrophilicity of unfilled Mater-Bi/PCL and biocomposite containing unmodified filler.

The potential of Hylocereus polyrhizus peel (HPP) as a new eco-friendly reinforcement for thermoplastic sago starch/agar composite (TPSS/agar) was investigated. The integration of HPP into TPSS/agar composite aimed to enhance its mechanical and thermal characteristics. The study employed Fourier transform-infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC), as well as mechanical, physical properties and soil burial testing to analyse the composites. The results showed a favourable miscibility between the matrix and filler, while at higher concentrations of HPP, the starch granules became more visible. The tensile and impact properties of the composites improved significantly after incorporating HPP at 20 wt%, with values of 12.73 MPa and 1.87 kJ/m2, respectively. The glass transition temperature (Tg) and initial decomposition temperature (Ton) decreased with the addition of HPP. The density of the composites reduced from 1.51 +/- 0.01 to 1.26 +/- 0.01 g/cm3 as the HPP amount increased. The environmental properties indicated that the composites can be composted, with weight loss accelerating from 35 to 60 % and 61 to 91 % by the addition of HPP in 2- and 4-weeks' time, respectively. The study demonstrates the potential of TPSS/agar/HPP composites as eco-friendly materials for various applications.

The PBAT (poly (butylene adipate- co-terephthalate) is a promising biodegradable material. However, it is often blend with hydrophilic polymers since its degradation rate in the aquatic environment is still limited. In this study, the blend PBAT/TPS (thermoplastic starch) films, namely BFs, were prepared by a blow extrusion approach, and evaluated for hydrolysis in four studied mediums acid (HCl, 1 M, 2 M, and 3 M), alkaline (NaOH, pH = 9, 11, and 13), phosphate buffer (pH = 7.4), and artificial seawater. The hydrolyzed BFs were characterized by weight loss, mechanical properties, scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), and differential scanning calorimetry (DSC). A larger starch content in the BFs caused hydrolysis more quickly. The highest hydrolytic rate was found in the alkaline solution, followed by the acid medium. The complete abiotic hydrolysis of the BFs was 3 M HCl for 14 days or NaOH (pH 13) for 35 days. After 180 days of incubation, the film containing 70.5 % PBAT/TPS granules has been associated with the highest biodegradation rate of 76.31 % in composting.