Search Results (574)

A novel low-cost poly(propylene carbonate-co-epichlorohydrin) (PPC-ECH) with mechanical properties similar to those of poly (butylene adipate-co-terephthalate) (PBAT) was developed and incorporated into a poly(propylene carbonate-co-phthalate) (PPC-P) matrix. Meanwhile, 4, 4’-diphenylmethane diisocyanate (MDI) was employed as a reactive compatibilizer and mixed with PPC-P and PPC-ECH to create a variety of PPC-P/PPC-ECH/MDI blends. The effects of PPC-ECH and MDI content on the mechanical, optical, thermal, morphological, and gas barrier properties of the blends were systematically investigated. Results demonstrated that MDI reacts with both PPC-P and PPC-ECH, forming a chemically bonded interface that significantly improves their compatibility. Notably, when 2 phr of MDI was incorporated, the elongation at break of the PPC-P/PPC-ECH/2MDI blend increased dramatically from 71% to 502%, while maintaining good tensile strength (~23 MPa) and light transmittance (~80%). To further enhance the gas barrier performance, a high-oxygen-barrier poly(vinyl alcohol) (PVA)/tannic acid (TA) complex coating was applied to the surface of the PPC-P/PPC-ECH/2MDI film. This coating synergistically leveraged the abundant hydroxyl groups in PVA and TA to form a dense hydrogen-bonded network, reducing oxygen permeability to an ultra-low value of 0.1 cm³·mm/(m²·day). This outstanding performance highlights the strong potential of PPC-P/PPC-ECH-based films for advanced packaging applications. Full article

Biodegradable active packaging that incorporates food-grade additives offers a promising solution for extending shelf life and minimizing food waste. This study investigates the development of functional packaging films for cheese applications by blending thermoplastic starch (TPS) and poly (butylene adipate-co-terephthalate) (PBAT) in a 60/40 (w/w) ratio with various concentrations of sodium lactate (SL; 1–7% w/w) using blown-film extrusion. Spectroscopic analyses, including ¹H NMR and FTIR, confirmed the presence of hydrogen-bonding and ionic interactions between the hydroxyl (–OH) groups of thermoplastic starch (TPS) and the carboxylate (–COO⁻) groups of sodium lactate, which enhanced interfacial compatibility and produced smoother, more compact film morphologies. SL acted as a multifunctional plasticizer and compatibilizer, improving film flexibility while slightly reducing tensile strength. Notably, SL incorporation increased water vapor permeability and surface wettability but significantly decreased oxygen permeability to below 1 cc·mm/m²·day·atm. At moderate concentrations (≥ 3% w/w), SL also exhibited antimicrobial activity against Staphylococcus aureus. When applied to cheese packaging, SL-modified films effectively maintained color stability for up to 9 days under refrigerated storage. Notably, cheeses packaged with films containing 3–7% (w/w) SL exhibited significantly lower hardness values than the control on day 3, indicating improved moisture retention and texture preservation, although these differences were no longer significant by day 9. These findings demonstrate that sodium lactate can simultaneously enhance interfacial miscibility, oxygen barrier performance, and antimicrobial functionality in sustainable, biodegradable active packaging systems. Full article

This study investigates the processability and performance limits of high-density polyethylene (HDPE) recovered from mixed polyolefin waste under realistic mechanical recycling conditions. The waste stream was processed by extrusion and injection molding, with parameters actively adapted. ATR-FTIR and DSC analysis confirmed HDPE as the matrix, contaminated with minor fractions of polypropylene (PP), PET, and polyurethane (PU). The reprocessed material exhibited a single melting peak at 132 °C and a melt flow rate (MFR) of 9.9 ± 0.6 g 10 min⁻¹, indicative of moderate degradation. Mechanical testing revealed reduced tensile strength and elongation at break compared to virgin HDPE, indicating compositional heterogeneity and poor interfacial adhesion. Field emission scanning electron microscopy (FESEM) revealed dispersed inclusions and microvoids acting as stress concentrators, consistent with reduced ductility. Crucially, progressive reduction of back pressure during processing optimization was essential for stabilizing melt flow and minimizing shear-induced degradation. This adjustment enabled consistent mold filling despite the material’s variability. The results demonstrate that mixed HDPE waste can be successfully valorized for non-structural applications such as plastic lumber or pallets, providing a sustainable pathway for recycling heterogeneous streams without costly pre-treatment or compatibilization. Full article

Thermoplastic starch (TPS) blended with biodegradable polyesters such as polyhydroxybutyrate (PHB), polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL) represents a promising route toward sustainable alternatives to petroleum-based plastics. TPS offers advantages related to abundance, low cost, and biodegradability, while polyesters provide improved mechanical strength, thermal stability, and barrier performance. However, the intrinsic incompatibility between hydrophilic TPS and hydrophobic polyesters typically leads to immiscible systems with poor interfacial adhesion and limited performance. This review critically examines recent advances in the development of TPS/polyester blends, with emphasis on compatibilization strategies based on chemical modification, natural and synthetic compatibilizers, bio-based additives, and reinforcing agents. Particular attention is given to the role of organic acids, essential oils, phenolic compounds, nanofillers, and natural reinforcements in controlling morphology, crystallinity, interfacial interactions, and thermal–mechanical behavior. In addition, the contribution of bioactive additives to antimicrobial and antioxidant functionality is discussed as an emerging multifunctional feature of some TPS/polyester systems. Finally, current limitations related to long-term stability, scalability, and life cycle assessment are highlighted, identifying key challenges and future research directions for the development of advanced biodegradable materials with tailored properties. Full article

This study investigates the reuse of mechanically recycled polyester–glass thermoset scraps (PS) as fillers in LDPE and HDPE matrices at 10–50 wt.% loading. Composites were produced through mechanical size reduction, single-screw extrusion, and compression molding without compatibilizers, and their mechanical and microstructural properties were systematically evaluated. LDPE composites exhibited a notable stiffness increase, with tensile modulus rising from 318.8 MPa (neat) to 1245.6 MPA (+291%) and tensile strength improving from 9.50 to 11.45 MPa (+20.5%). Flexural performance showed even stronger reinforcement: flexural modulus increased from 0.40 to 3.00 GPa (+650%) and flexural strength from 14.5 to 35.6 MPa (+145%). HDPE composites displayed similar behavior, with flexural modulus increasing from 1.2 to 3.1 GPa (+158%) and strength from 34.1 to 45.5 MPa (+33%). Surface-treated fillers provided additional stiffness gains (+36% in sPL4; +33% in sPH3). Impact strength decreased with loading (LDPE: −51%, HDPE: −61%), though surface treatment partially mitigated this (+14–19% in LDPE; +13% in HDPE). Density increased proportionally (PL: 0.95 → 1.20 g/cm³, PH: 0.99 → 1.23 g/cm³), while moisture uptake remained low (≤0.25%). Optical and SEM analyses indicated increasingly interconnected fiber networks at high loadings, driving stiffness and fracture behavior. Overall, PS-filled polyolefins offer a scalable route for converting thermoset waste into functional semi-structural materials. Full article

Ethylene–vinyl acetate (EVA) copolymers are widely used in packaging, films, foams, and adhesives because of their softness and optical clarity; however, their relatively low mechanical strength limits broader applications. In this study, a scalable masterbatch strategy was developed to reinforce EVA by introducing TEMPO-oxidized cellulose nanofibers (T-CNFs), pre-encapsulated within an ethylene–vinyl alcohol (EVOH) matrix. EVOH acted as a compatibilizer, establishing robust hydrogen bonding with T-CNFs (evidenced by a 2.73-fold increase in the hydrogen bonding index) and thereby promoting their uniform dispersion and strong interfacial adhesion in the hydrophobic EVA phase. The resulting nanocomposites demonstrated significant improvements in mechanical performance, achieving a maximum 1.54-fold increase in tensile strength and a 1.42-fold increase in Young’s modulus compared to neat EVA. These findings highlight a practical route to produce bio-based, mechanically enhanced EVA nanocomposites with potential for industrial-scale applications. Full article

The article studies the influence of chlorosulfonated polyethylene CSM 40 as a compatibilizer on the curing characteristics of the rubber compound, dynamic mechanical analysis, morphology, physico-mechanical and performance properties of vulcanized rubber based on a compound of ethylene propylene diene monomer EPDM S 501A and nitrile butadiene NBR 2645 rubbers. DMA studies indicate that the temperature dependence of tanδ for vulcanizates with and without a compatibilizer based on EPDM S 501A/NBR 2645 at a ratio of 75/25 parts per hundred parts of rubber (phr) has a bimodal character, which indicates the incompatibility of the rubber phases. The temperature dependence for EPDM S 501A/NBR 2645 vulcanizates (25/75 phr) with and without a compatibilizer has a monomodal form, which characterizes the improved compatibility of the rubber phases. SEM showed that a clearly defined microporous structure is observed on a cleavage of vulcanizate sample EPDM/NBR (25/75 phr) without a compatibilizer; with the addition of CSM 40, this feature is retained, but becomes less pronounced. It is shown that vulcanizates containing the compatibilizer CSM 40 are characterized by increased strength properties and hardness compared to vulcanized rubber without a compatibilizer. It was established that the vulcanized rubber based on EPDM S 501A/NBR 2645/CSM 40 (25/75/5 phr) is characterized by the smallest changes in the elastic-strength properties and hardness of vulcanizates after a day of thermo-oxidative aging in air and their weight after exposure to industrial oil I-20A and standard petroleum fluid SZhR-1 at room temperature among vulcanizates based on EPDM S 501A and NBR 2645. The vulcanizate of the rubber compound, including a compound of EPDM/NBR (25/75 phr) with a compatibilizer CSM 40 in an amount of 5 phr (2.88 wt.%), is characterized by stable physico-mechanical properties and improved performance properties. This rubber compound can be used for the manufacture of rubber products operating under the influence of oils and hydrocarbon environments. Full article

Poly(lactic acid) (PLA) has strong potential for use in sustainable packaging, automotive components, and structural materials; however, its inherent brittleness and limited thermal stability restrict broader application. To overcome these drawbacks, this study developed PLA-based composites reinforced with mica and compatibilized using poly(vinyl butyral) (PVB). To overcome the inherent brittleness and limited thermal stability of poly(lactic acid) (PLA), this study investigated the incorporation of mica as a reinforcing filler into PLA and PLA/poly(vinyl butyral) (PVB) composite systems. Five types of mica with varying particle sizes and densities were examined to evaluate their influence on the mechanical, thermal, and rheological properties of the composites. The PLA/PVB blend was prepared in an 8:2 weight ratio, and mica was added at 5 phr (35 g). PLA/mica composites showed limited improvement in mechanical performance due to poor interfacial compatibility between PLA and mica, resulting in decreased tensile strength and non-uniform filler dispersion. In contrast, the addition of PVB, a tough and flexible polymer containing hydroxyl groups (ca. 20 mol%) remaining after polymerization, significantly enhanced the interfacial interaction with mica and improved filler dispersion within the matrix. As a result, PLA/PVB/mica composites exhibited increased tensile strength and toughness. Thermal analysis revealed that mica restricted polymer chain mobility, leading to higher glass transition temperatures, while PVB promoted a more uniform crystalline structure. Rheological studies indicated that PLA/PVB/mica composites had higher complex viscosity and lower melt flow index (MFI) due to increased molecular interactions and reduced chain mobility. Notably, certain mica types containing Ca²⁺ ions catalyzed chain scission during melt processing, leading to reduced molecular weight and increased MFI. These findings demonstrate that the synergistic combination of PVB and mica can effectively improve the processability and performance of PLA-based composites, offering a promising route for developing sustainable materials for advanced applications. Full article

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biodegradable polyester considered for food packaging, though its mechanical and barrier limitations pose challenges. This study assessed PHBV/TiO₂ nanocomposites for packaging applications. Differential scanning calorimetry revealed reduced crystallinity and lower melting points with an increase in TiO₂ content. Thermal stability improved at 1% and 3% TiO₂, raising onset temperatures to 283 °C and 284 °C, respectively. Scanning electron microscopy and FTIR confirmed uniform nanoparticle dispersion without agglomeration. Tensile tests showed decreasing strength and modulus from 1% to 7% TiO₂, with peak elongation at 3%, whereas viscosity behavior declined with higher nanoparticle loading. Low portions of nanoparticles (1% and 3%) induced the improvement in barrier properties against oxygen and water vapor. The highest biodegradation rate occurred at 7% TiO₂. Overall, the nanocomposites’ properties tend to deteriorate with the addition of higher portions of TiO₂. Thus, despite some improvements, the nanocomposites did not deliver consistent, multi-property enhancements to justify use in food packaging. Key metrics like sealability and appearance were not evaluated. Future research should explore surface-treated TiO₂, alternative fillers, compatibilizers, and optimized processing, alongside standardized safety assessments for food-contact applications. Full article

In the context of increasing resource scarcity and environmental concerns, the development of green composite materials is essential for promoting sustainability in the automotive industry. However, poor interfacial compatibility between plant fibers and polypropylene (PP), as well as the performance deterioration under complex environmental aging conditions, severely limits their engineering applications. In this study, a synergistic interfacial modification strategy combining alkali treatment of hemp fibers (HFs) with polypropylene grafted maleic anhydride (PP-g-MAH) was employed to enhance fiber–matrix interaction. Hemp fiber-reinforced polypropylene composites (HFRPs) with varying fiber contents (7.5–30 wt%) were fabricated via injection molding. Accelerated aging tests were conducted on the compatibilized HFRPs for up to 2400 h under ultraviolet–thermal–moisture coupled conditions, in accordance with the SAE J2527 standard. The evolution of surface color, mechanical properties, chemical structure, and microstructure was systematically characterized. After aging, surface whitening of the composites was observed. Tensile strength and impact strength decreased by 9.57–22.12% and 38.68–46.03%, respectively, while flexural strength remained relatively stable due to the supporting effect of the fiber skeleton. The aging of compatibilized HFRPs follows an outside-in progressive degradation mechanism, characterized by a stepwise cascade of surface oxidation, crack propagation, moisture ingress, interfacial degradation, and mechanical performance deterioration. These findings offer valuable insights into the long-term durability of natural fiber-reinforced thermoplastic composites and provide theoretical and practical guidance for their structural design and application in demanding service environments. Full article

The paper presents the results of experimental testing of a PLA-based composite, modified with powdered cork and a compatibilizer. The purpose of applying these additives was to evaluate their influence upon the physical, structural and functional properties of the obtained material. Specimens with various cork and compatibilizer contents were analyzed to evaluate the synergic interaction between the polymer base and the filler. The tests of the mechanical properties, water absorption and FTIR analysis were carried out. The results confirmed that the cork filler improved the PLA-based composite both in terms of the utility and ecological aspects. Despite a certain mechanical deterioration, the properties remain fully acceptable for packaging applications. Also, the improvement of hardness at higher cork content was observed, which points to effective phase interaction and a good adherence of the components. The FTIR spectroscopy confirmed chemical stability of the base and the lack of unwanted degradation reactions. The obtained composite is an innovative, biodegradable polymer material that utilizes natural waste in a way which is both economic and environmentally friendly. The obtained results point to a high application potential of this kind of composite, mainly in the packaging industry and in the field of ecological utility materials. Full article

Objective. To determine how bamboo loadings (2.5–5 wt%) and compatibilization with PBAT-g-MAH (BP-1, 10 wt%) affect melt flow and early-time mineralization of PLA biocomposites under near-ambient soil–compost conditions (ASTM D5988), while using PBAT-g-GMA (BP-2) only as a melt-flow screening reference. Methods. Melt flow index (MFI, ASTM D1238, 2.16 kg; 190/210/230 °C) was first measured for neat PLA and PLA/BP-1/BP-2 blends to select a printable matrix. PLA/10BP-1 composites containing 2.5–5 wt% bamboo were then compounded, extruded as bars for biodegradation tests, and validated by FFF printing. Biodegradation was quantified from titrimetric CO₂ evolution in soil–compost reactors at 21 ± 2 °C and pH ≈ 7 (triplicate specimens plus triplicate blanks; mean ± SD and endpoint statistics). ATR-FTIR was used to support mechanistic interpretation. Results. BP-1 markedly increased MFI relative to neat PLA, whereas BP-2 remained close to the neat matrix, consistent with epoxy-driven coupling that can raise viscosity. Under ambient burial, all materials exhibited very low mineralization over 0–23 days; PLA/10BP-1/2.5B and PLA/10BP-1/5B showed a slight increase in net CO₂ evolution compared with neat PLA, but the differences remained modest and within the experimental uncertainty, reflecting a balance between bamboo’s pro-hydrolytic effect and the sealing action of PBAT-g-MAH compatibilization. Significance. The data delineate a printing–degradation window in which PLA/10BP-1 with 2.5–5 wt% bamboo combines easy processing and short-term durability while preserving industrial compostability at end-of-life. Full article

A 3D printing filament was fabricated from poly(lactic acid) (PLA), cassava pulp (CP), and epoxy using a twin-screw extruder. Several bio-composites were synthesized by varying the amount of epoxy (0.5, 1.0, 3.0, 5.0, and 10.0 wt.%). The size of the CP fibers significantly affected the surface quality, filament diameter, and mechanical properties of the final product. The smallest fiber size (45 µm) provided a smooth surface and consistent diameter. Incorporating 1 wt.% of epoxy into PLA/CP enhanced the tensile strength (56.6 MPa), elongation at break (6.2%), and hydrophobicity of the composite. The composite mechanical properties deteriorated at epoxy contents above 1 wt.% due to the amplified plasticizer effect of excessive epoxy. The optimized PLA/CP/epoxy formulation was used to generate the 3D filament. The resultant filament displayed a tensile strength of 64.6 MPa and elongation at break of 9.8%, attributed to the fine morphology achieved via thorough mixing provided by the twin-screw extruder. Epoxide-mediated crosslinking between PLA and CP enabled the development of a novel 3D printing filament with excellent mechanical properties. This research illustrates how agricultural residues can be upcycled into high-performance biomaterials with innovation in sustainable manufacturing, inclusive economic growth, reducing reliance on petroleum-based plastics and thus providing benefits regarding human health, climate change mitigation, plastic in the ocean, and environmental impacts. Full article

This study quantifies the mechanical behavior of 10–15 mm thick WPC boards compression-molded from post-consumer bottle-cap polyolefins (PP/HDPE, 70/30 wt%) and pine sawdust (0, 10, 20 wt%). Flexural and tensile strength/modulus are determined and application-oriented acceptability assessed for non-structural temporary concrete formwork under ASTM bending and tension protocols. Mechanical performance was evaluated using three-point and four-point bending tests, as well as axial tension. Flexural strengths averaged 17.31, 16.38, and 8.71 MPa for 0, 10, and 20 wt% sawdust (three-points), and 15.23, 13.18, and 9.20 MPa (four-points), with flexural moduli as high as 1.60 GPa (four-points). Tensile strengths averaged 3.60, 3.79, and 3.44 MPa, with tensile elastic moduli of 0.10, 0.33, and 0.36 GPa, respectively. Stress–strain curves showed a nonlinear elastic-brittle response without a defined yield point, followed by fracture, consistent with porous, non-compatibilized WPCs. Variability increased with the sawdust content, reflecting the distribution of filler and matrix-fiber adhesion. Although the properties are inferior to those of conventional building materials, the results are within the application-oriented ranges for non-structural temporary formwork (as established by the reported ASTM tests). UV durability associated with carbon black-pigmented caps is presented as a literature-supported hypothesis for future accelerated aging, rather than as a measured outcome. Overall, the findings demonstrate a circular-economy pathway that converts post-consumer plastics and sawmill waste into WPC panels for sustainable construction. Full article

Thermoset pultrusion waste was mechanically recycled as vinyl ester–glass (RVC) filler and compounded—without compatibilizers—into LDPE and HDPE (10–50 wt.%) by single-screw extrusion and compression molding. In LDPE, flexural strength increased from 15 MPa to over 30 MPa, and the modulus rose more than fourfold, with the 30 wt.% composition showing the best strength-stiffness balance. For HDPE, tensile modulus improved by more than 300%, and flexural strength reached about 36 MPa at 20–30 wt.% loading. Impact toughness also improved markedly, particularly for LDPE, where the absorbed energy more than doubled. SEM and optical analyses linked optimum performance to 20–30 wt.% filler content, while higher loadings caused agglomeration and void formation. The study demonstrates a scalable route to valorize thermoset waste into functional polyolefin composites for circular material design. Full article