Polymers最新文献

This study examined the thermal degradation of pulverized Musa sapientum (banana) peel waste through thermogravimetric measurements and thermokinetic modelling. For the first time, it also incorporated backpropagation deep learning to model pyrolysis traces, enabling the prediction and optimization of the process. Physicochemical characterization confirmed the material's lignocellulosic composition. TGA was performed between 30 and 950 °C at heating rates of 5, 10, 20, and 40 °C min^-1, identifying a primary devolatilization range of 190 to 660 °C. The application of a backpropagation machine learning technique to the processed TGA data enabled the estimation of arbitrary constants that accurately captured the characteristic behaviour of the experimental data (R2~0.99). This modelling and simulation approach achieved a significant reduction in training loss-decreasing from 35.9 to 0.07-over 47,688 epochs and 1.4 computational hours. Sensitivity analysis identified degradation temperature as the primary parameter influencing the thermochemical conversion of BP biomass. Furthermore, analyzing deconvoluted DTG traces via Criado master plots revealed that the 3D diffusion model (Jander [D3]) is the most suitable reaction model for the hemicellulose, cellulose, and lignin components, followed by the R2 and R3 geometrical contraction models. The estimated overall activation energy values obtained through the Starink (STK) and Friedman (FR) model-free isoconversional kinetic methods were 82.8 ± 3.3 kJ.mol^-1 and 97.6 ± 3.9 kJ.mol^-1, respectively. The thermodynamic parameters estimated for the pyrolysis of BP indicate that the formation of activated complexes is endothermic, endergonic, and characterized by reduced disorder, thereby establishing BP as a potential candidate material for bioenergy generation.

Substance-based medical devices (SBMDs) are increasingly used in wound care due to their favorable safety profile, physicochemical mechanisms of action, and therapeutic effectiveness. These products often incorporate biopolymers such as hyaluronic acid or chitosan, alone or in combination with antimicrobial agents like silver nanoparticles (AgNPs) or silver sulfadiazine (SSD), offering hydration, tissue protection, and control of microbial burden in both acute and chronic wounds. Despite their widespread clinical use, the regulatory classification of SBMDs under Regulation (EU) 2017/745 (MDR) remains one of the most challenging and debated areas within the current European framework. This review analyzes the scientific and regulatory context of topical SBMDs, with particular emphasis on borderline products that share similarities with medicinal products in terms of formulation, composition, or claimed effects. The discussion focuses on the application of MDR Annex VIII, specifically Rule 21 for substance-based devices and Rule 14 for devices incorporating medicinal substances with ancillary action, together with interpretative guidance provided by MDCG 2022-5 Rev.1 and the Association of the European Self-Care Industry (AESGP) Position Paper. Particular attention is given to the identification of the critical role of the primary mode of action (MoA) as the determining criterion for regulatory qualification, especially for products containing antimicrobial substances. Through selected examples and case analyses, the review highlights inconsistencies in classification across Member States and underscores the need for a more harmonized, evidence-based, and proportionate regulatory approach. Overall, SBMDs challenge traditional regulatory boundaries and call for a framework capable of accommodating complex, multifunctional products while ensuring patient safety and regulatory coherence.

Polymethylmethacrylate (PMMA) bone cement is widely used in orthopedics, accounting for approximately 80% of knee joint replacements in the United States. While prosthesis designs and materials have evolved to improve performance and durability, PMMA cement has undergone minimal compositional changes. Carbon-based nanomaterials, particularly graphene oxide (GO), have attracted interest for their ability to enhance the mechanical and thermal properties of orthopedic cements. This study evaluated the effects of incorporating different GO concentrations into PMMA bone cement on its mechanical properties, cytocompatibility, and antibacterial activity. PMMA was modified with GO at 0.1, 0.25, and 0.5 weight percent (wt%) for mechanical and antibacterial tests, and at 1.0 wt% for cytocompatibility. Mechanical performance was assessed via four-point bending tests. Cytocompatibility was evaluated using mouse embryonic fibroblasts (NIH/3T3), and antibacterial activity was tested against Staphylococcus aureus using a modified direct contact assay. GO incorporation significantly increased Young's modulus (0.1% and 0.25%, p = 0.009) and improved tensile strength (p = 0.0015) and flexural strength (p = 0.025) at 0.1%. Cytocompatibility remained comparable to the control (p = 0.873). Antibacterial activity was concentration dependent, with 0.25% and 0.5% GO maintaining significant bacterial inhibition up to 48 h, whereas 0.1% showed no sustained effect. Overall, 0.25 wt% GO provided the most suitable balance between mechanical integrity and antibacterial performance, indicating that PMMA-GO bone cements with this composition can combine enhanced mechanical properties with relevant antibacterial activity without compromising biocompatibility, and are therefore promising candidates for orthopedic applications.

Industrial effluents include toxic chemicals, particularly heavy metals, that remain in the environment and jeopardize human and ecological health. This research synthesized hybrid biosorbents (HBs) for the extraction of Cr (III) from wastewater by using sugarcane bagasse, banana peels, and orange peels in conjunction with magnetite at ratios of 1:2, 1:1, and 2:1. The synthesized biosorbents-MSC, MBP, and MOP-were characterized using FTIR, XRD, TEM, BET, and SEM/EDX, therefore validating their structural, functional, morphological attributes and elementary composition. Batch studies showed MBP (1:1) to be the most efficient sorbent, with over 80% removal of Cr (III). Optimization experiments indicated that the peak removal efficiency (92.10%) was achieved at an initial concentration of 100 mg/L, a pH of 3, a dose of 0.4 g/100 mL, and a contact duration of 60 min. Isotherm analysis revealed that adsorption adhered to a homogeneous monolayer mechanism, optimally characterized by the Langmuir Type 1 model (R² = 0.9688), whereas kinetic analysis demonstrated that the pseudo-second-order model (R² = 0.9419) yielded the most accurate fit. MBP (1:1) has significant promise as an economical and sustainable biosorbent for the efficient removal of Cr (III) from wastewater.

Polybutadiene has excellent mechanical properties and flexibility. It is widely used in elastomers and industrial fields. However, it has the characteristic of high flammability. The low LOI and rapid heat release upon ignition pose significant fire hazards. This results in a significant fire safety risk during service. Therefore, its application in some key fields has been restricted. In this study, polybutadiene with high-performance flame-retardant properties was developed by adding phosphorus-nitrogen synergistic flame retardants to address this challenge. This flame retardant mainly enhances its flame retardancy through the synergistic gas-phase and condensed-phase mechanisms. Dense and continuous carbon layers could be promoted by flame retardants during combustion. It provides an effective thermal barrier and oxygen barrier. In addition, phosphorus-containing volatiles can function by suppressing flame propagation via radical quenching in the gas phase. The modified polybutadiene reached UL-94 V-1 grade at the optimal load of 1.0 wt%. Meanwhile, its LOI increased to 27%. The cone calorimeter test further confirms a high reduction in peak heat release rate (pHRR). This work provides a feasible strategy for developing advanced polybutadiene materials. It can effectively enhance its fire safety. At the same time, it maintains a balance between flame retardancy and the overall material performance.

This work investigated the stabilization mechanisms and β-carotene encapsulation characteristics of cellulose nanofibrils (CNFs) stabilized Pickering emulsions (PE) prepared by different emulsification processes. For 48 days of storage, ultrasound-prepared Pickering emulsions (US-PE) stabilized by at least 2.0 wt.% CNFs have obvious cream stabilization, and high-pressure homogenization-prepared Pickering emulsions (HPH-PE) stabilized by over 1.6 wt.% CNFs have excellent cream stabilization. The stabilization of HPH-PE, which was superior to that of US-PE, mainly relied on the steric stabilization of CNFs' space networks. Although the encapsulation efficiency of β-carotene in US-PE was higher than that in HPH-PE when the CNF concentration was over 1.2 wt.%, the retention rate of β-carotene in US-PE was obviously lower than that in HPH-PE. So, the internal space structure of CNF-stabilized HPH-PE was conducive to stabilizing the emulsion and protecting the bioactive molecule.

This work focused on the development of eco-friendly bio-composites based on polylactic acid (PLA) and sugarcane bagasse (SCB) as a natural fiber from Moroccan vegetable waste. First, the fiber surface was treated with an alkaline solution to remove non-cellulosic components. Then, the composite materials with various amounts of treated sugarcane bagasse (TSCB) were fabricated using two routes, melt processing and solvent casting. The primary objective was to achieve high fiber dispersion/distribution and homogeneous bio-composites. The dispersion properties were analyzed using scanning electron microscopy (SEM). Subsequently, the thermal, mechanical, and melt shear rheological properties of the obtained PLA-based bio-composites were investigated. Through a comparative approach between the dispersion state of fillers with extrusion/injection molding and solvent casting method, the work aimed to identify the most suitable processing route for producing PLA-based composites with optimal dispersion, improved thermal stability, and mechanical reinforcement. The results support the potential of TSCB fibers as an effective bio-based additive for PLA filament production, paving the way for the development of eco-friendly and high-performance materials designed for 3D printing applications. Since the solvent-based route did not allow further improvement and presents clear limitations for large-scale or industrial implementation, the transition toward 3D printing became a natural progression in this work. Material extrusion offers several decisive advantages, notably the ability to preserve the original morphology of the fibers due to the moderate thermo-mechanical stresses involved, and the possibility of manufacturing complex geometries that cannot be obtained through conventional injection molding. Although some printing defects may occur during layer deposition, the mechanical properties obtained through 3D printing remain promising and demonstrate the relevance of this approach.

This study presents an environmentally sustainable finishing approach for hemp fabrics by combining soy protein isolate (SPI) pretreatment with an in situ infrared (IR)-assisted synthesis of zinc oxide nanoparticles (ZnO NPs). IR heating was employed to reduce energy consumption while promoting efficient nanoparticle formation compared to conventional thermal processing, while SPI acted as a bio-based stabilizer to enable uniform ZnO NP distribution on the fabric surface. Transmission electron microscopy revealed predominantly spherical to polyhedral ZnO NPs with minimal agglomeration, and X-ray diffraction confirmed their characteristic wurtzite crystalline structure. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy mapping further verified the homogeneous deposition of ZnO NPs on hemp fibers. The treated fabrics exhibited multifunctional performance, showing significantly enhanced ultraviolet (UV) protection with a UV protection factor (UPF) of 50+ compared with untreated hemp. Antibacterial activity against Staphylococcus aureus and Escherichia coli was confirmed by the AATCC TM147 test, while a quantitative AATCC TM100 assessment demonstrated an excellent antibacterial efficiency of 99.99% bacterial reduction against S. aureus. Additionally, the incorporation of 2 wt% SPI significantly improved fabric hydrophilicity and wettability. Overall, this work demonstrates a green and effective strategy for producing antibacterial and UV-protective hemp textiles.

Poly(lactic acid) (PLA) has emerged as a leading bio-based polymer due to its renewability, processability, and biodegradability, yet its broader adoption remains constrained by limitations in thermal stability, mechanical performance, and end-of-life control. This review provides a comparative and application-oriented overview of recent advances in PLA from synthesis and catalyst landscapes to structure-property-biodegradation relationships and practical applications. Representative polymerization routes and catalyst systems are critically compared in terms of achievable molecular weight, stereochemical control, scalability, and sustainability. Key structure-property modification strategies-including stereocomplex formation, blending, and copolymerization-are quantitatively evaluated with respect to thermal and mechanical properties, highlighting inherent trade-offs. Importantly, environment-specific biodegradation behaviors are assessed using representative quantitative metrics under industrial composting, soil, marine, and enzymatic conditions, underscoring the strong dependence of degradation on both material design and testing environment. Finally, application-driven requirements for food packaging, fibers, and agricultural materials are discussed alongside regulatory considerations, processing constraints, and qualitative cost positioning relative to conventional polymers. By integrating recent representative studies into comparative tables and synthesis-driven discussions, this review offers design guidelines for tailoring PLA-based materials toward targeted performance and sustainable deployment.

Wearable healthcare is shifting from passive tracking to active, closed-loop care by integrating polymeric three-dimensional (3D)-printed microneedle arrays (MNAs) with soft electronics and wireless modules. This review surveys the design, materials, and the manufacturing routes that enable skin-conformal MNA wearables for minimally invasive access to the interstitial fluid and precise but localized drug delivery. Looking ahead, the converging advances in multimaterial printing, nano/biofunctional coatings, and artificial intelligence (AI)-driven control are promising "wearable clinics" that can personalize monitoring and therapy in real time, thus accelerating the translation of MNA-integrated wearables from laboratory prototypes to clinically robust, patient-centric systems. Overall, this review identifies a clear transition from proof-of-concept MNA devices toward integrated, wearable, and closed-loop therapeutic platforms. Key challenges remain in scalable manufacturing, drug dose limitations, long-term stability, and regulatory translation. Addressing these gaps through advances in hollow MNA architectures, system integration, and standardized evaluation protocols is expected to accelerate clinical adoption. However, the realization of closed-loop wearable MNA-based systems remains constrained by challenges related to power consumption, real-time data latency, and the need for robust clinical validation.