Search Results (59)

Sustainable structural composites can significantly lower vehicle-related emissions. To evaluate the recycling of different composite materials, laboratory-scale pyrolysis was conducted and assessed both technically and environmentally. Two demonstrators were studied: a truck side skirt made from natural flax and hemp fibres with polypropylene (PP), and a car front header composed of glass fibres and PP. Additional materials examined included thermoplastic composites containing polyamide 6 (PA6), bio-based polyamide 11 (PA11) and thermoset polyester. Results showed that material type strongly influenced the pyrolysis outcome, product composition and recycling potential. Glass fibres could be recovered and reused as reinforced fibres, while natural fibres could be recovered as biooil for potential use in biofuel production. Polymers were recovered as pyrolysis products that, depending on their composition, can be used in different applications, from recovering monomers from PA6 to producing hydrocarbons that may replace naphtha (from PP) or aromatics (from polyester) in the petrochemical industry. Life cycle assessment (LCA) findings revealed that the climate impact of composite recycling is primarily driven by the environmental burdens of the recycling process itself and by the ability of recovered materials and chemicals to substitute conventional fossil-based alternatives. Efficient recycling pathways are therefore essential to maximising environmental benefits. Full article

The increasing demand for sustainable and environmentally friendly construction materials has spurred interest in biopolymer composites reinforced with agricultural waste. Rice husk (RH), a byproduct of rice milling, is abundant and rich in lignocellulosic fibers and silica, making it excellent for use in fiber-reinforced biopolymers. The novelty of this study lies in its integrated and construction-oriented evaluation of rice husk (RH)-reinforced biopolymers, combining mechanical, thermal, environmental, and economic perspectives within a single framework. The study introduces a novel comparative approach by benchmarking multiple polymer matrices-including PP, recycled HDPE, epoxy, PLA, and bio-binders-under unified quantitative performance criteria. Another key novelty is the identification of the dual functional role of silica-rich RH in simultaneously enhancing structural strength and flame retardancy while contributing to carbon emission reduction. With a high silica content (15–20%) and lignocellulosic structure, RH serves as a natural filler that enhances the performance of polymer matrices such as polypropylene (PP), epoxy, polylactic acid (PLA), and recycled polyethylene. Mechanically, RH-reinforced composites demonstrate significant improvements in tensile, flexural, and impact strength. For example, PP composites with NaOH-treated RH and coffee husks achieved tensile strengths between 27.4 MPa and 37.4 MPa, with corresponding Young’s modulus values ranging from 1656 MPa to 2247.8 MPa. Recycled HDPE-RH blends reached tensile strengths up to 74 MPa and flexural values of 39 MPa, validating their structural applicability. Epoxy matrices embedded with 0.45 wt.% RH nanofibers showed degradation thresholds of 411 °C and 678 °C, reflecting substantial thermal resistance. Flame retardancy is further improved by the presence of RH biochar, which leads to reduced peak heat release rate (PHRR) and enhanced char formation. In building insulation applications, RH-based composites exhibit low thermal conductivity values between 0.08 and 0.14 W/m·K, contributing to energy efficiency. Economically, RH reduces material costs by 30–40%, while environmentally, its integration lowers carbon emissions in PP composites by up to 10%, and promotes biodegradability. Despite challenges such as moisture absorption and interfacial adhesion, these can be mitigated through alkali treatment, compatibilizers (e.g., MAPP), or hybrid reinforcement strategies. Full article

This study presents a comparative Life Cycle Assessment (LCA) of packaging for 1000 kg of fresh-cut salad using conventional polypropylene (PP) and bio-based INZEA^® FH05 bags. Using the Product Environmental Footprint (PEF) methodology, the analysis revealed weighted scores of 152 ± 14 mPt for PP and 158 ± 14 mPt for the bioplastic. To distinguish between statistical significance and practical relevance, a Monte Carlo Analysis (MCA) was performed. Statistical significance was defined by the probability P(PP ≥ INZEA^®), representing the frequency of iterations where the PP impact was greater than or equal to the bioplastic, while practical relevance was assessed by the percentage difference (Δ) between mean values. The MCA demonstrates that the PP system is the environmentally preferable option in 91.5% of the simulated iterations; correspondingly, there is only an 8.5% probability (P) that PP results in a higher impact than the bioplastic. Despite this high frequency of preference, the overall tangible benefit remains modest, with a 4.1% reduction (Δ) in the total PEF score for PP. At the characterization level, bioplastic films showed a robust advantage in fossil resource depletion (P = 96.2%; Δ = +4.7% for PP); however, this was offset by significantly higher impacts in categories such as Acidification (P = 0%; Δ = −11.0%) and Freshwater Ecotoxicity (P = 0%; Δ = −29.7%). Conversely, the Climate Change category showed environmental parity with no tangible benefit (Δ = −0.5%) and a lack of statistical significance (P = 43%). These findings indicate that the theoretical benefits of compostability are currently hindered by industrial infrastructural deficiencies. Under current scenarios, PP maintains a competitive environmental profile, highlighting that a successful transition to bioplastics requires both material innovation and systemic improvements in waste management infrastructure. Full article

This paper introduced a simple, efficient method to prepare mechanically strong lignin-based foams (lignofoams) with open-cell structures using a facile baking technique. The self-expansion of lignin occurred without any additional chemical blowing agents, foaming agents, plasticizers, or lubricants. During heating, kraft lignin softened, and the internal water, either initially adsorbed or generated in situ through the dehydration of hydroxyl groups, acted as a natural blowing agent for foaming a porous foam structure. Incorporating a small amount of polypropylene (PP) enhanced mechanical properties by coating the inner walls of open cells. The porous, softened composite was then cooled to room temperature and solidified into the self-expanded lignofoam. The resulting lignofoams exhibited tunable densities ranging from 0.21 to 0.49 g/cm³ and a maximum compressive strength of 3.6 MPa. The lignofoam also showed excellent thermal insulation properties with low thermal conductive coefficients (0.057–0.098 W/mK). These features highlight the great potential of lignofoam for a bio-based thermal insulation material for construction applications. Full article

Synthetic plastics are polymers that are largely produced worldwide, impacting ecosystems and human health. Microplastics are produced from fragmentation and degradation of larger plastics, as a consequence of environmental factors. Low-density polyethylene (LDPE) and polypropylene (PP) are plastic polymers acting as environmental hazards. Challenges in effective plastic waste management include sustainable and environmentally responsible approaches like microbial degradation. In this work, a shotgun metagenomic approach has been applied to analyze the response of the microorganisms living on plastic surfaces (plastispheres) of LDPE and PP to biodeterioration of these plastics (BioProject-NCBI, PRJNA1378224). Low-density polyethylene and polypropylene materials were collected from a waste landfill of intensive greenhouse agriculture. A further functional analysis supported putative roles of enzymes that could be involved in the initial steps of biodeterioration of LDPE and PP, including sarcosine oxidases; bromo- and chloro-peroxidases; cytochrome P450 and alkane monooxygenases; and multicopper oxidases. A CheckM analysis of genes that code for these oxidative enzymes revealed that they were mainly from the bacterial Phyllobacterium genus (Rhizobiaceae family) and, in less abundance, from the archaeon Methanoculleus genus (Methanoculleaceae family). This study supports putative roles of sarcosine oxidases and bromoperoxidases, and other relevant enzymes, in bacterial and archaeal LDPE and PP biodeterioration, highlighting the genomic potential of the microbiomes under study in biodeterioration of these synthetic plastics. Full article

The increasing use of biodegradable plastics derived from renewable sources (PLA, PHB, PBAT, and others) in the packaging industry raises controversies and risks related to potentially integrating these plastics into municipal waste streams, which may significantly hinder future recycling efforts. This publication addresses this issue by investigating a selected bio-based and biodegradable commercial mixture of poly(lactic acid) and poly(butylene adipate terephthalate) (PLA/PBAT), referred to as (BIO), in blends with polypropylene (PP) and polystyrene (PS). The blends were prepared with three different mass contents of 1, 5, and 10 wt.% using (PP) and (PS) as base materials. The effects of introducing biodegradable and bio-based plastics into municipal waste streams (PCR—Post-Consumer Recycling), which typically contain polypropylene, various grades of polyethylene, and polystyrene, remain unknown. The purpose of the study was to assess the consequences of contaminating municipal waste destined for recycling (using PP and PS as examples) with small amounts (between 1 and 10%) of BIO plastics. The designed experiment and the obtained results simulate the expected presence of BIO contamination in future PP and PS recyclates. The prepared mixtures were subjected to injection molding to produce test specimens, which were then analyzed for changes in their physical properties such as tensile strength, impact strength and hardness. Thermal properties were assessed using Differential Scanning Calorimetry (DSC), while dynamic properties were analyzed at variable temperatures using Dynamic Mechanical Thermal Analysis (DMTA). The tests provided insights into how the addition of selected, but insignificant ratios (of 1 to 10%) of biopolymers affects the properties of (PP) and (PS) compared to materials without content of biopolymers. The conducted tests of mechanical properties (static and dynamic) and thermomechanical properties have shown that the change in the properties of the mixture depends not only on the amount of biodegradable polymer but also on the nature of the load. It would be advisable to analyze mechanical properties in relation to the duration of the load; therefore, a long-term load analysis is necessary. For dynamic tests, a decrease in impact strength was demonstrated with increasing biodegradable polymer content in the produced mixtures. Similar behavior was recorded for hardness measurements. The results underscore the need for continued research, given the valuable findings for processors and the advancement of mechanical recycling technologies. Full article

In the context of the urgent global transition toward sustainable materials, this study presents a comparative environmental life cycle assessment (LCA) of poly(3-hydroxybutyrate) (PHB), a biodegradable, bio-based polymer, against conventional petrochemical plastics (polystyrene—PS; polypropylene—PP) and another popular biopolymer, namely polylactic acid (PLA). The LCA was conducted using primary production data from a laboratory-scale PHB manufacturing process, integrating real-time energy consumption measurements across all production stages. Environmental indicators such as carbon footprint and energy demand were analyzed under cradle-to-gate and end-of-life scenarios. The results indicate that PHB, while offering biodegradability and renewable sourcing, currently exhibits a significantly higher carbon footprint than PP, PS, and PLA, primarily due to its energy-intensive downstream processing. However, the environmental impact of PHB can be markedly reduced—by over 67%—through partial integration of renewable energy. PLA demonstrated the lowest production-phase emissions, while PP showed the most favorable end-of-life outcomes under municipal waste management assumptions. The study highlights the critical influence of energy sourcing, production scale, and waste treatment infrastructure on the sustainability performance of biopolymers. These findings provide practical insights for industry and policymakers aiming to reduce the environmental burden of plastics and support a shift toward circular material systems. Full article

Energy demand in the building sector has drastically increased due to rising occupant comfort requirements, accounting for 30% of the world’s final energy consumption and 26% of global carbon emissions. Thus, to improve building efficiency in heating and cooling applications, phase change material (PCM)-based passive thermal management techniques have been considered due to their energy storage capabilities. This study provides a comprehensive review of the research on PCM applications, types, and encapsulation forms. Various solutions have been proposed to enhance PCM performance. In this review, the authors suggest new methods to improve PCM efficiency by using the multilayered wall technique, which involves employing two layers of a hybrid bio-composite—specifically, the hybrid hemp/wood fiber-reinforced composite with a polypropylene (PP) matrix—along with a layer of PCM made from spent coffee grounds (SCGs). Previous studies have shown that oil extracted from SCGs demonstrates good thermal and chemical stability, as it contains approximately 60–80% fatty acids, with a phase transition temperature of approximately 4.5 ± 0.72 °C and latent heat values of 51.15 ± 1.46 kJ/kg. Full article

Because of their many health benefits, blueberries are highly sought after as superfoods. There are also ongoing initiatives to enhance sustainability in blueberry packaging by selecting appropriate materials. Ideal packaging should ensure the safe delivery of the fruit to consumers while maintaining product quality, addressing environmental concerns, and promoting circularity. The environmental impact of four different packaging materials was assessed using a comparative cradle-to-grave life cycle assessment. The materials evaluated included a cardboard package (CB), a cardboard package with a cellulose lid (CBC), a polypropylene (PP) as a control, and a punnet made from rice straw topped with polylactic acid (RPLA), a bio-based plastic. The evaluation considered all environmental impact categories, utilizing Sphera GaBi software and the CML 2016 method. Special attention was given to various end-of-life scenarios, determining energy resources and fossil abiotic depletions. The results indicate that RPLA is the most eco-friendly option, with the lowest carbon footprint and energy resources. CB has a larger carbon footprint but less overall impact than traditional incineration, while CBC has the highest impact during recycling, mainly due to marine ecotoxicity. PP has a relatively low impact on energy resources and fossil abiotic depletion compared to CB and CBC packaging materials. Full article

The increasing demand for sustainable road construction materials necessitates innovative solutions to overcome the challenges of Recycled Asphalt Pavement (RAP), including aged binder brittleness, reduced flexibility, and durability concerns. Waste Plastic Aggregates (WPA) offer a promising alternative; however, their thermal aging behavior and interactions with RAP remain insufficiently understood. This study evaluates the performance of RAP-based asphalt mixtures, incorporating three types of WPA—Low-Density Polyethylene (LDPE), High-Density Polyethylene (HDPE), and Polypropylene (PP)—under three thermal aging conditions: mild (60 °C for 7 days), moderate (80 °C for 14 days), and severe (100 °C for 30 days). The mixtures were designed with 30% RAP content, 10% and 20% WPA by aggregate weight, and SBS-modified binder rejuvenated with 2% and 4% sewage sludge bio-oil by binder weight. It is considered that thermal aging may impact the performance of WPA in RAP mixtures; therefore, this study evaluates the durability and mechanical properties of RAP mixtures incorporating LDPE, HDPE, and PP under varying thermal aging conditions to address these challenges. The results showed that incorporating WPA and bio-oil significantly enhanced the mechanical performance, durability, and sustainability of asphalt mixtures. Marshall Stability increased by 12–23%, with values ranging from 12.6 to 13.2 kN for WPA-enhanced mixtures compared to 12.7 kN for the control. ITS improved by 15–20% in dry conditions (1.34–1.44 MPa) and 12–18% in wet conditions (1.15–1.19 MPa), with TSR values reaching up to 82.64%. Fatigue life was extended by 28–43%, with load cycles increasing from 295,600 for the control to 352,310 for PP mixtures. High-temperature performance showed a 12–18% improvement in softening point (57.3 °C to 61.2 °C) and a 23% increase in rutting resistance, with rut depths decreasing from 7.1 mm for the control to 5.45 mm for PP mixtures after 20,000 passes. These results demonstrate that combining RAP, WPA, and bio-oil produces sustainable asphalt mixtures with superior performance under aging and environmental stressors, offering robust solutions for high-demand applications in modern infrastructure. Full article

Nanoarchitectonics influences the properties of objects at micro- and even macro-scales, aiming to develop better structures for protection of product. Although its applications were analyzed in different areas, nanoarchitectonics of food packaging—the focus of this review—has not been discussed, to the best of our knowledge. The (A) structural and (B) functional hierarchy of food packaging is discussed here for the enhancement of protection, extending shelf-life, and preserving the nutritional quality of diverse products including meat, fish, dairy, fruits, vegetables, gelled items, and beverages. Interestingly, the structure and design of packaging for these diverse products often possess similar principles and methods including active packaging, gas permeation control, sensor incorporation, UV/pulsed light processing, and thermal/plasma treatment. Here, nanoarchitechtonics serves as the unifying component, enabling protection against oxidation, light, microbial contamination, temperature, and mechanical actions. Finally, materials are an essential consideration in food packaging, particularly beyond commonly used polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polyvinyl chloride (PVC) plastics, with emphasis on biodegradable (polybutylene succinate (PBS), polyvinyl alcohol (PVA), polycaprolactone (PCL), and polybutylene adipate co-terephthalate (PBAT)) as well as green even edible (bio)-materials: polysaccharides (starch, cellulose, pectin, gum, zein, alginate, agar, galactan, ulvan, galactomannan, laccase, chitin, chitosan, hyaluronic acid, etc.). Nanoarchitechnotics design of these materials eventually determines the level of food protection as well as the sustainability of the processes. Marketing, safety, sustainability, and ethics are also discussed in the context of industrial viability and consumer satisfaction. Full article

Biodegradable polymers are essential for sustainable plastic life cycles and contribute to a carbon-neutral society. Here, we explore the development of biodegradable fibers with excellent mechanical properties using polypropylene (PP) and thermoplastic starch (TPS) blends. To address the inherent immiscibility between hydrophobic PP and hydrophilic TPS, hydrophilic modification and a masterbatch approach were employed. Melt-spinning trials demonstrated that the modified PP and TPS blends (mPP/TPS) exhibited excellent spinnability and processability comparable to virgin PP. A sheath-core configuration was introduced to enhance biodegradability while maintaining structural stability, with an mPP-rich part as the core and a TPS-rich part with a biodegradable promoter (BP) as the sheath. SEM and DSC analyses confirmed strong interfacial compatibility, uniform fiber morphology, and single melting points, indicating no phase separation. Mechanical testing showed that the sheath-core fibers met industrial requirements, achieving a tenacity of up to 2.47 gf/den and tensile strain above 73%. The addition of a BP increased the biodegradability rate, with PP/TPS/BP fibers achieving 65.93% biodegradation after 115 days, compared to 37.00% for BP-free fibers. These results demonstrate the feasibility of blending petroleum-based polymers with bio-based components to create fibers that balance biodegradability, spinnability, and mechanical performance, offering a sustainable solution for industrial applications. Full article

Microplastics (MPs), as frequent pollutants, persist in aquatic environments and have an impact on the growth and biomass production of microalgae. This study employed MPs of polyethylene (PE), polystyrene (PS), and polypropylene (PP) at concentrations of 250 mg/L with MP sizes of 50, 100, 300, and 500 µm to investigate their influences on the growth and bio-production of Scenedesmus quadricauda. The results revealed that MPs suppressed the growth of S. quadricauda and increased algal lipid production. The order of the MPs in terms of their inhibitory and lipid production effect was the following: PP > PS > PE. The order of their size sensitivity was 50 > 100 > 300 > 500 µm. In the 50 µm PP culture, the inhibition of microalgal growth (inhibition rate: 49.26%) and accumulation of lipids (total lipid content: 65.40%) were most significant, especially with neutral lipid content. Additionally, scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analyses proved that the rough MP surface led to high aggregation of microalgae, reduced the intensities of the protein-, lipid-, and carbohydrate-related bands and affected the structure of the algal cells. Full article

The buildup of abandoned plastics in the environment and the need to optimize agricultural waste utilization have garnered scrutiny from environmental organizations and policymakers globally. This study presents an assessment of the thermal decomposition of date seeds (DS), polypropylene homopolymer (PP), and their composites (DS/PP) through experimental measurements, machine learning convolutional deep neural networks (CDNN), and kinetic and thermodynamic analyses. The experimental measurements involved the pyrolysis and co-pyrolysis of these materials in a nitrogen-filled thermogravimetric analyzer (TGA), investigating degradation temperatures between 25 and 600 °C with heating rates of 10, 20, and 40 °C.min⁻¹. These measurements revealed a two-stage process for the bio-composites and a decrease in the thermal stability of pure PP due to the moisture, hemicellulose, and cellulose content of the DS material. By utilizing machine learning CDNN, algorithms and frameworks were developed, providing responses that closely matched ($R^2~0.942$) the experimental data. After various modelling modifications, adjustments, and regularization techniques, a framework comprising four hidden neurons was determined to be most effective. Furthermore, the analysis revealed that temperature was the most influential parameter affecting the thermal decomposition process. Kinetic and thermodynamic analyses were performed using the Coats–Redfern and general Arrhenius model-fitting methods, as well as the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose model-free approaches. The first-order reaction mechanism was identified as the most appropriate compared to the second and third order F-Series solid-state reaction mechanisms. The overall activation energy values were estimated at 51.471, 51.221, 156.080, and 153.767 kJ·mol⁻¹ for the respective kinetic models. Additionally, the kinetic compensation effect showed an exponential increase in the pre-exponential factor with increasing activation energy values, and the estimated thermodynamic parameters indicated that the process is endothermic, non-spontaneous, and less disordered. Full article

Various plastics and biomass wastes, such as polypropylene (PP), low- or high-density polyethylene (LDPE/HDPE), and lignin, have become some of the most concerning wastes nowadays. In this context, this study aimed to investigate the possibility of applying thermochemical processes for the valorization of these materials. The experiments were carried out using a thermogravimetric analyzer on individual plastic and lignin samples and their mixtures at different mass ratios of 1:1, 1:2, 1:3, and 1:4. The gaseous products evolved during the pyrolysis process were analyzed by combined thermogravimetric and Fourier-transform infrared spectroscopy (TG-FTIR) and chromatography-mass spectrometry (Py-GC/MS) to analyze the functional groups and chemical composition of the obtained pyrolysis products. The results showed that the main functional groups of lignin monitored by TG-FTIR were aromatic and aliphatic hydrocarbons, while all plastics showed the same results for hydrocarbons. The investigation confirmed that mixing these types of plastics with lignin at different mass ratios led to increased recovery of higher-value-added products. Py-GC/MS analysis showed that the greatest results of compound recovery were achieved with lignin and LDPE/HDPE mixtures at 600 °C. At this temperature and with a mass ratio of 1:3, the plastic’s radicals enhanced the depolymerization of lignin, encouraging its wider decomposition to hydrocarbons that can be applied for the production of value-added chemicals and bio-based energy. Full article