Journal of Polymers and the Environment最新文献

Efficient in vitro expansion of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) requires biocompatible, xenofree culture surfaces. Here, Tamarindus indica L. seed kernel powder (TKP) was evaluated as a natural, cost-effective alternative to xenogenic gelatin. Preliminary phytochemical screening and GC–MS profiling confirmed bioactive compounds in TKP. FTIR and XRD analyses revealed functional groups and structural differences compared to gelatin (GEL) and regular tissue culture dishes (TTP), supporting enhanced hUC-MSC adhesion and proliferation. SEM demonstrated the favourable surface roughness of TKP coatings. DPPH assay showed 51.35% radical scavenging at 1 mg/mL with an IC₅₀ of 0.96 mg/mL. MTT assay indicated 90% cell viability at 2% TKP. Optimized TKP coating (2%, 0.1 mL/cm² area) enabled efficient expansion at passages P0–P2, yielding 0.7 × 10⁶ cells/mL (95% viability) on TKP and 0.82 × 10⁶ cells/mL (94% viability) on GEL. AO/EtBr staining confirmed higher viable cell numbers on TKP against GEL and TTP. Flow cytometry (CD90⁺, CD105⁺, CD31⁻) and RT-PCR (CD90, CD73, CD105) verified retention of hUC-MSC markers. All experiments were performed in triplicate; results are mean ± SD, with p < 0.05. Culturing hUC-MSCs on TKP in human platelet lysate (HPL) media establishes a fully xenofree system. Collectively, TKP represents a sustainable, bioactive coating for scalable hUC-MSC culture, offering a promising alternative to conventional gelatin-based surfaces for regenerative applications. Although TKP enables efficient hUC-MSC expansion, potential batch-to-batch variability, unexamined protein expression under diverse culture conditions, and the absence of long-term or in vivo validation highlight the need for further studies.

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Herein, a novel potential ink for 3D bio-printing, composed of itaconic acid and 1,4-butanediol, was prepared and analyzed. This study investigated the effect of curing time on UV-crosslinked polymer films. The degree of curing was studied using FTIR and gel content analyses. The evaluation of thermal properties was conducted using DSC and TG analyses. The mechanical properties of the polymer films were evaluated using bending strength, tensile strength, and DMA analyses. Some of the polymer films were investigated for their cytotoxicity (cell viability > 80% for every investigated material). The proposed poly(tetramethylene itaconate) (PBItc) with DEAP photoinitiator as a composition remains underexplored. The UV-crosslinked polymer films exhibit good mechanical properties (Young’s Modulus = 0.32–1.64 GPa) and thermal properties (heat resistance = 116–130 °C). PBItc films underwent acidic, hydrolytic, and alkaline degradation for 60 days (remaining mass > 80%). The properties of the PBItc films show potential for applications in tissue engineering scaffolds with slower biodegradation rates.

Glycerol migration in thermoplastic starch/poly(lactic acid)/poly(butylene adipate-co-terephthalate) (TPS/PLA/PBAT) blends presents a critical challenge by compromising melt stability, interfacial adhesion, and mechanical performance. This study reveals that strategic control of twin-screw extrusion parameters can induce a processing-driven multiscale physicochemical confinement, effectively limiting glycerol diffusion and thereby eliminating the requirement for external additives. Comprehensive characterization via oscillatory shear rheology, capillary rheometer, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy, differential scanning calorimetry, and Fickian diffusion modeling reveals that optimized conditions enhance TPS dispersion and interfacial adhesion. The effective glycerol diffusion coefficient decreased by approximately 38% with increased screw speed at 180 °C and by around 69% with elevated temperature at 180 rpm. The combination of morphological and rheological evidence elucidates a confinement mechanism induced by processing. SEM directly verified interfacial expansion resulting from shear, while a distinct viscoelastic relaxation mode, serving as a rheological fingerprint, was identified. We interpret this confinement to arise from a synergy of three effects: the partial weakening of hydrogen-bond relaxation in the TPS-glycerol network, polarity-mediated interfacial resistance that enhances tortuosity, and the encapsulation of refined TPS microdomains by the PLA/PBAT matrix. The latter critically depletes accessible –OH groups and prolongs bulk diffusion pathways. The established processing window (≈ 190 °C, 180–200 rpm) ensures sustained melt processability while suppressing diffusion, as evidenced by a coefficient of around 1.23 × 10⁻⁷ cm² s⁻¹, a 48% reduction from the 170 °C baseline. This synergy between processing parameters and material properties offers a controllable route to stabilize plasticizer content and tailor morphology in TPS-based systems.

To enhance the biological activity of Sargassum fusiforme, a brown algae, polysaccharides were extracted and degraded using two methods: ultrasound-assisted hydrochloric acid (yielding U-SFP) and α-amylase-assisted hydrolysis (yielding M-SFP). A Box-Behnken response surface design (BBRS) was used to optimize the degradation conditions. Structural changes before and after treatment were analyzed, including molecular weight variations during in vitro digestion. The relationship between the structural characteristics and antioxidant activity of the degradation products was established, revealing significant impacts on surface morphology, solubility, crystallinity, and triple-helix structure. The DPPH radical-scavenging activities of U-SFP and M-SFP were 0.106 mg/mL and 0.045 mg/mL, respectively, compared to 0.029 mg/mL for native SFP. Similarly, the ferric reducing power of both U-SFP and M-SFP was significantly higher than that of native SFP. These results demonstrate that controlled degradation enhances the antioxidant capacity of Sargassum fusiforme polysaccharides, highlighting their potential for industrial and biomedical applications.

Microplastics continue to weather as they linger in the environment, yet the roles of polymer type and product formulation in shaping their aging trajectories remain poorly defined. In this work, we examined how commercial polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) microplastics respond to ultraviolet C (UVC) irradiation across doses from 0 to 40 MJ m^-2. Among the three materials, PP changed the most rapidly: its carbonyl index (CI) rose sharply, its melting temperature (T_m) dropped from 157 °C to 141 °C, and its crystallinity (χ_c) declined from 76% to 52%. In contrast, PE and PET showed only modest alterations in their chemical and thermal signatures. Imaging by scanning electron microscopy further highlights the divergence in aging behavior—PP surfaces developed widespread cracks and generated secondary fragments, whereas the other polymers remained comparatively intact. Given that surface oxidation precedes bulk destabilization, we incorporated an infrared (IR)-based surface-crystallinity index (χ_sI) to quantify these early chemical-structural changes. The influence of formulation is investigated using two PP laboratory wastes—transparent centrifuge tubes and blue pipette-tip boxes—both of which show progressive surface cracking, increasing CI, and T_m depression as the UVC dose rises, with the colored material aging faster than the transparent PP. Because aging manifests through several properties that do not evolve in parallel, direct comparisons across polymers and products are challenging. An approach based on principal component analysis integrates CI, T_m, χ_c, and χ_sI into a single quantitative aging score. This unified metric provides an approach for harmonized evaluation of aging levels across polymer types, product formulations, and physicochemical properties. The resulting framework facilitates direct comparisons between materials and provides predictive assessment of microplastic transformation under environmental or laboratory exposure conditions.

This study presents the chemical, thermal and mechanical characterization of two bio-based and fully-recyclable epoxy latent resins derived from pine oil, engineered to meet high-performance mechanical and thermal specifications for advanced composite applications. The characterized latent epoxy resins exhibited glass transition temperature (T_g) values ranging between 90 and 120 °C, flexural strength and modulus values within the range of 35–110 MPa and 2.5–3.2 GPa, respectively, making them suitable for structural applications. One of the latent epoxy resin was further employed in the fabrication of a hybrid joint comprising metal and CFs reinforced composites characterized by an average ILSS of 11.9 MPa and a maximum load of 1429.2 N, due to a good mechanical interlocking at the metal/CFs interface. Due to its latent curing behavior, the epoxy resin remains stable until exposed to elevated temperatures (≥ 80 °C), at which point cross-linking is initiated. This property affords an extended pot life and improved control during application and assembly. This feature makes the system especially attractive for hybrid manufacturing approaches, where the extended open time supports accurate positioning of fibers and metal inserts. Furthermore, the epoxy resin was cross-linked by using a cleavable amine hardener to achieve full recyclability, so enabling disassembly under mild acidic controlled conditions. This property facilitated the full recovery of constituent raw materials through a targeted chemical recycling process, achieving a 100% recovery yield. The proposed system offers a sustainable alternative to conventional thermoset-based hybrid metal/CFs composite manufacturing and end-of-life management. This class of hybrid joints can find industrial applications in aerospace and automotive sectors, in electronic and optical applications, in sports equipment and biomedical devices, for the manufacturing of next-generation structural solutions, with enhanced performance and versatility, by also supporting the global shift toward circular design and responsible material use.

Biodegradable polymers are currently the focus of intense research due to their biodegradability and potential to replace conventional plastics. However, they still face several limitations: high cost, limited large-scale production, and faster decline of its properties over time, which compromises its performance and durability. Their complex molecular structures, combined with the strong influence of physical, chemical, and environmental factors, make their performance difficult to predict with traditional methods. These complexities highlight the need for advanced modeling approaches capable of capturing nonlinear and high-dimensional behaviors. Machine learning (ML) and deep learning (DL) offer promising tools in this context. Their application to biodegradable polymers can improve predictions of aging behavior and lifetime under different environmental conditions, guide the design of biodegradable polymers, identify optimal synthesis and processing parameters for extended service life and detect complex patterns in large datasets. This review discusses experimental techniques commonly used to evaluate the aging of biodegradable polymers and examines recent applications of ML and DL in this field. It also links experimental data with ML/DL models and outlines the key challenges and future perspectives for integrating these approaches into biodegradable polymer research.

The replacement of petroleum-based plastics with sustainable, biodegradable alternatives is a key challenge in the transition toward a circular economy. Zein, a maize-derived protein, is a promising candidate for biodegradable thermoplastics, but its limited ductility and processability have hindered wider adoption. This study addresses this gap by exploring the effect of apricot shell flour (ASF) on zein (ZEI) thermoplastic materials plasticized with 25 wt% diethylene glycol (DEG) and processed by extrusion and injection molding. To date, the use of DEG as a plasticizer for zein in thermoplastics and the incorporation of ASF as a synergistic filler–plasticizer in such systems have not been reported, defining the novelty of this work. Mechanical analysis revealed an outstanding ductility. ZEI-DEG exhibited a strain at break of 57.2%, which was increased to 119.2% with 15% ASF, while impact strength rose from 6.4 to 15.9 kJ/m², confirming a synergistic plasticization effect between DEG and ASF. A decrease in glass transition was observed by dynamic mechanical thermal analysis with the incorporation of ASF, probably due to the interaction of uronic acids present in ASF with DEG and zein through hydrogen bonding. Morphology analysis showed good filler dispersion and good compatibility with the zein matrix. Thermogravimetric analysis (TGA) revealed a slight decrease in thermal stability with ASF, but materials remained stable up to 350 °C. Materials exhibited a progressive darkening with dark brown colors, providing a wood-like appearance that is potentially attractive for sustainable wood plastic composite applications such as packaging. The properties of these materials were far higher than the traditionally glycerol-plasticized zein materials. Overall, these findings highlight ASF as a promising bio-based filler that enhances flexibility and toughness of thermoplastic zein while maintaining good thermal behavior and creating aesthetically appealing natural composites. These green materials offer significant potential for biodegradable food packaging, furniture, and interior design products.

Chitosan (CH) is a biopolymer with strong potential for sustainable food packaging applications. However, this is hindered due to its poor water resistance and limited mechanical performance. To overcome these limitations, this study proposes an easy modification strategy based on the in-situ radical polymerization of itaconic acid (IA) directly within the CH film-forming solution, resulting in CH-based films incorporating poly(itaconic acid) (PIA) in a single step. The incorporation of 10% IA increased the water contact angle from 87.3° to 92.3° and reduced moisture content from 23.8 to 21.1%. Thermal stability was improved, and tensile strength increased by approximately 50% compared to the unmodified film. These enhancements are attributed to intermolecular interactions and partial grafting of PIA chains onto CH, as supported by FTIR, XRD, and SEM analyses. Hence, the direct synthesis of PIA during film formation offers a simple yet effective modification of CH, enhancing water resistance, thermal stability, and mechanical properties, positioning CH/PIA films as strong candidates for food packaging applications.

In this study, nano-hydroxyapatite (n-HAp) was extracted from pink perch fish scales (PPFS) using a simple and efficient alkaline hydrolysis method. The obtained n-HAp was characterized through XRD, FTIR, Raman spectroscopy, TGA, SEM, and TEM. Various concentrations of n-HAp (0.25, 0.5, 0.75, and 1 wt%) were then incorporated into a polylactic acid (PLA) matrix using solution blending followed by blown film extrusion. The influence of n-HAp on the thermal, mechanical, and biodegradable properties of the PLA-based composites was systematically analyzed. FTIR and Raman spectroscopy confirmed chemical bonding between n-HAp and the PLA matrix in the blown films. Thermal analysis via TGA revealed an increase in the initial degradation temperature compared to neat PLA, attributed to the presence of n-HAp. DSC analysis showed a reduction in glass transition temperature and crystallinity, which restricted polymer chain mobility and increased the amorphous phase. Mechanical property evaluation through tensile testing demonstrated that lower concentrations of n-HAp significantly enhanced elongation at break, with PLA_HAp 0.75 exhibiting improved flexibility and an increase in elongation compared to neat PLA. A 180-day soil biodegradability study indicated that incorporating 0.5 wt% n-HAp into the PLA matrix accelerated the hydrolysis process by 500%, enhancing the overall degradation of the PLA_HAp composite film. These findings highlight the potential of n-HAp in improving the functional properties of PLA-based composites for food packaging applications.