Abstract Microwave (MW) assisted rapid synthesis procedure was implemented to prepare polyvinyl alcohol/n-hydroxyapatite bio-composite scaffolds (PVA/agarose/n-HAp (PAH)) using agarose as a crosslinker. The MW-assisted synthesis with two heating cycles (600 and 900 W) allowed the fastest formation and homogenous distribution of n-HAp within the polymeric matrix. The freeze-drying process was used to fabricate a porous bio-composite. The average crystallite size of the synthesized n-HAp was 9.7 nm. The MW-assisted method took only 8–10 min to synthesize n-HAp, while the conventional method took 24 h. The obtained bio-composites were highly porous and the porosity obtained for PAH1 and PAH3 were 62 % and 65 %, respectively. However, the porosity decreased to nearly half (31 % and 38 % for PAH2 and PAH4, respectively) while doubling the n-HAp content. The highest swelling was obtained for PAH3 in both water and PBS at 167 % and 498 %. The highest tensile strength and modulus were obtained for PAH1 at 29 MPa and 1.4 Gpa which is higher than the tensile strength and modulus of Conv. PAH (20 MPa and 0.74 GPa, respectively) and many porous PVA/HAp scaffolds reported. The fabricated scaffolds are biocompatible, porous, possess good mechanical properties, and are suitable for application in bone tissue engineering.
Abstract Self-standing polymer films require improved mechanical strength, thermal stability, and resistance to microbial growth for practical coating and barrier applications. This study developed self-standing chitin/montmorillonite (MMT) nanocomposite films with enhanced mechanical, thermal, and antimicrobial properties. Chitin/MMT films (0–15 wt% MMT) were fabricated via a low-temperature NaOH/urea system and ethanol coagulation, followed by cation-exchange intercalation of benzyldimethylstearylammonium chloride (C18-BAC). Comprehensive structural characterizations, including XRD, FTIR, and FESEM, confirmed the successful intercalation of C18-BAC and uniform MMT dispersion at optimal loadings. The 3 wt% MMT composites exhibited the highest tensile strength (42.3 MPa, a 10.5 % improvement) while maintaining >80 % optical transparency. Thermal stability progressively increased with MMT content. Crucially, antimicrobial assays demonstrated a predominantly non-leaching, contact-active mechanism against Staphylococcus aureus , Bacillus subtilis , and Escherichia coli , overcoming the limitations of diffusion-based release. The optimized 3 wt% formulation significantly reduced biofilm biomass by 68.4 % for B. subtilis , 65.2 % for S. aureus , and 54.1 % for E. coli relative to controls. These findings highlight that controlled MMT incorporation and C18-BAC intercalation effectively tune the macromolecular architecture of chitin films. The developed system offers a sustainable, non-leaching antimicrobial coating with strong potential for active food packaging applications.
Improving thermal conductivity by directly blending filler with epoxy resin (ER) is often not ideal. The key is solving the dispersion of filler particle in matrix, which is crucial for establishing thermal conductive network. To achieve it, by utilizing the tannic acid (TA) modification and the alkali treatment of boron nitride (BN), OH-BN and BN@TA were obtained. Then, the chitosan-based framework was prepared via directional freezing method, where OH-BN or BN@TA acted as filler. Finally, the acquired framework was soaked in ER mixture, and the compound was cured to fabricate a new-type thermal conductive modified-BN/ER composite. The results indicated that the filler was uniformly dispersed, well adhered and directionally arranged within the framework, causing the formation of efficient thermal conductive pathway. The derived ER composite had good thermal stability with the decomposition temperature over 200 degrees C. Moreover, the thermal conductivity of ER composite exhibited maximum improvement rate of 210 % when the filling ratio of BN@TA was 30 wt%. The got ER composite could quickly transfer the heat, demonstrating its good heat dissipation capability. This study provided a new route to attain safe and efficient thermal conductive ER composite, which had great application prospect in the field of thermal management.
Different bioplastics, such as polylactic acid (PLA) and cellulose, are increasingly used in fresh food packaging because they can constitute integrated and complex preservation systems while increasing sustainability. In this work, the biodegradation of the different components of an integrated packaging system composed of a rigid PLA tray, a heat-sealed PLA film, and cellulose sachets inside is discussed. Biodegradation tests were carried out both under composting and soil burial conditions, both based on the cumulative evolved CO2. The different packaging components were cut into 1 & times; 1 cm squares to facilitate biodegradation. Nonbiodegradable polymeric materials were included in the tests for comparison. After 60 days, biodegradation between 11.5 and 22.7 % was obtained for PLA under composting conditions, while biodegradation of 3.0-6.8 % was obtained under soil conditions, respectively. The thickness of the PLA sheets considerably affected the degree of biodegradation under the two conditions. For cellulose sheets, biodegradation was 82.4 % and 85.1 % under composting and soil conditions, respectively, while in the case of nonbiodegradable polymers, the values obtained were less than 2.0 % after 60 days. The need arises for the previous separation and preconditioning of this type of material after use in integrated packaging, so that biodegradation occurs under the most favorable conditions.
Abstract Supercritical foaming of poly(butylene adipate-co-terephthalate) (PBAT) is governed by its crystallization kinetics and melt rheology, which is essential for the design of biodegradable polyester foams. However, systematic investigations on how co-components with distinct crystalline structures modulate PBAT crystallization, and how these changes impact melt rheology and foaming performance, are still lacking. To address this gap, PBAT-based blend foams with thermoplastic polyurethane (TPU), poly(butylene succinate) (PBS), and poly(propylene carbonate) (PPC) were prepared and analyzed using DSC, rheology, and foam characterization. The results show that at low additive contents, semi-crystalline TPU and PBS, as well as amorphous PPC, promote PBAT crystallization by providing heterogeneous nucleation sites, thereby enhancing bubble formation. However, the effect is modulated by the intrinsic properties of the additives. At higher contents, TPU and PBS progressively form independent crystalline phases, and foaming behavior becomes increasingly governed by their own characteristics: TPU crystalline domains restrict bubble growth, while PBS independent crystals reduce foam stability. PPC remains amorphous, but its plasticizing effect lowers melt viscosity, inhibiting foam expansion and narrowing the foaming window. Overall, PBAT foaming is governed by competition between additive crystalline structure and content-induced phase evolution, providing a basis for designing biodegradable foams with balanced expansion, structure, and mechanical properties.
Uncontrolled junctional hemorrhage remains a leading cause of preventable death in both civilian trauma and combat settings, as current hemostatic devices are often ineffective against deep, narrow penetrating wounds. In this study, we fabricated a highly expandable gelatin/polyvinyl alcohol (PVA) composite hemostatic sponge designed to address this critical gap. Using a combination of physical foaming, directional freezing, and compression-setting processes, the sponge was engineered to achieve rapid and substantial expansion (an 8-10-fold volume increase within 10 s) upon contact with blood. The material exhibited excellent biocompatibility, with a hemolysis rate of 1.3 % and no observable cytotoxicity toward L929 fibroblasts. In vitro whole blood clotting assays demonstrated rapid hemostatic efficacy, achieving 98 % clotting efficiency within 20 s. These results suggest that the gelatin/PVA composite sponge, with its dual mechanism of physical packing and active procoagulation, represents a promising candidate for controlling non-compressible hemorrhage in emergency and combat settings.
In this study, porous nylon 6 membranes were fabricated via decomplexation of nylon 6 in a methanol/CaCl2 system using the wet phase inversion method. The addition of CaCl2 significantly influenced the dissolution behavior of nylon 6 by increasing the viscosity of the casting solution, thereby modifying solvent-nonsolvent exchange during phase inversion and governing membrane formation. As a result, membrane morphology evolved from sponge-like to finger-like and mixed structures depend on CaCl2 concentration in the polymer casting solution, accompanied by changes in thickness, density, and crystalline structure. DSC analysis revealed a reduction in crystallinity from 26.0 +/- 1.0 % for pure nylon 6 to 18.9 +/- 1.3-24.2 +/- 0.8 % for the membranes, indicating suppressed formation of well-ordered crystalline domains during dissolution and coagulation. FTIR results further confirmed coordination between Ca2+ ions and amide groups, leading to conformational changes in the polymer chains. Water permeability exhibited a non-linear dependence on CaCl2 concentration, with the membrane prepared using 15 wt% CaCl2 showing the highest permeability (18.32 +/- 0.6 L m(-2) h(-1) bar(-1)) due to its highly interconnected porous structure. These findings demonstrate that CaCl2 concentration is an effective parameter for tailoring the structure-property-performance relationship of nylon 6 membranes for filtration and controlled drug delivery applications.
Polymer-based fiber-reinforced composites are widely used for lightweight automotive structural components due to their distinct functional properties compared to monolithic polymeric matrices. However, conventionally synthesized composites exhibit low fracture toughness and moderate thermal stability due to poor load transfer, limited energy dissipation at higher impact loads, and the susceptibility of natural fibers to degradation at elevated temperatures. The main objectives of the present research are to enrich the thermo-mechanical characteristics of polycarbonate (PC) based poly matrix composite embedded with short Kevlar fiber and 2-6 wt% of boron carbide nanoparticle (B4C) via the injection mould technique. During the production, the hybrid nanocomposite contained 10 wt% Kevlar fiber/4 wt% of B4C is facilitated a higher tensile stress of 108 MPa, improved fracture toughness of 4.2 MPa m0.5, high hardness of 94 HRR, reduced thermal expansion of 42 & times; 10-6 per degrees C, significant enhancement in thermal stability, and provide better heat deflection behaviour, which is superior to monolithic PC poly matrix without Kevlar fiber and B4C nanoparticles. An optimal combination of Kevlar fiber and B4C nanoparticles in the PC matrix is a trade-off for lightweight automotive cabinet and seat frame applications.
In injection moulding, the local melt front velocity is a function of the set injection volume flow and the part geometry. With an injection volume flow profile adapted to the part geometry, more homogenous melt front velocities and surface qualities can be achieved. In order to transfer simulative optimised injection volume flow profiles into machine settings, a process model is being developed that describes the loss volume flows in the plasticising unit and the progress of mould filling as a function of screw position on the basis of measured injection pressures. Using mould sensors on a part with different wall thickness, it is shown that the model is able to accurately determine the degree of filling and that the generated injection volume flow profiles effectively reduce the variance of the melt front velocity during mould filling by up to 70 %.
Abstract A novel layered rare-earth flame retardant, yttrium phenylphosphonate (YPP), was synthesized via a self-assembly solution route and employed as a synergistic agent with aluminum diethylphosphinate (AlPi) to enhance the fire safety of polyamide 66 (PA66). While the incorporation of 8.5 wt% AlPi alone improved the limiting oxygen index (LOI) to 29.0 %, it failed to achieve a V-0 rating. Incorporating merely 0.5 wt% YPP into the system (S7: 8.0 wt% AlPi/0.5 wt% YPP) resulted in a substantial performance leap, achieving a UL-94 V-0 rating with no melt dripping and an LOI of 32.3 %. Relative to neat PA66, the optimized composite demonstrated a 70.2 % reduction in peak heat release rate (PHRR) and a 15.0 % decrease in total heat release (THR). Concurrently, the char yield at 800 °C increased significantly from 0.6 % to 8.3 %. Thermogravimetric analysis coupled with infrared spectroscopy and X-ray photoelectron spectroscopy revealed a dual-phase mechanism: YPP promotes the formation of a thermally stable, phosphorus-yttrium crosslinked char network in the condensed phase, while AlPi releases phosphorus radicals to quench combustion in the gas phase. These findings establish the AlPi/YPP system as a highly efficient, halogen-free flame retardant strategy for engineering plastics, offering superior fire safety at significantly reduced additive loadings.
The conjugated polymer, poly(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene), was evaluated as a near-infrared photosensitizer on TiO2 electrodes for solar energy conversion. It was characterized through steady-state absorption, photoluminescence, spectro-electrochemical studies, and cyclic voltammetry. Cation generation and excited state decay dynamics with 560-nm excitation in solution and on TiO2 films with different electrolyte concentrations were also studied using femtosecond transient/pump-probe spectroscopy. A significant difference in the relaxation processes was observed when in solution versus adsorbed onto TiO2-coated quartz substrates. A slow ground state bleach (similar to 20 ps) and slower recoveries were exhibited in solution, whereas a quick ground state bleach and quick recovery along with excited state absorption peaks were observed on TiO2 films, confirming electron injection. Charge transfer from the excited polymer to TiO2's conduction band was also suggested from DFT calculations, and was estimated by time-correlated single photon counting (TCSPC) measurements. Although devices exhibited modest efficiency and photocurrent, the TCSPC results indicated an increase in the electron injection efficiency in the presence of electrolytes, which suggests that the careful selection of electrolytes plays a role in the energetics of solar cell fabrication. Modest experimental efficiencies were also observed from increasing localized charge distributions on molecular orbitals of the polymer molecules with increasing length.
TiO2 nanoparticles were synthesized by a sol-gel method and calcined at 400 degrees C and 700 degrees C to obtain anatase and rutile powders, respectively. The aim of this work was to investigate the effect of TiO2 crystalline phase and filler loading on the dielectric and electrical properties of PVA-PEG-PVP nanocomposite membranes. Polymer nanocomposites were prepared by incorporating TiO2 (5-25 wt%) into a PVA-PEG-PVP blend containing 10 wt% PEG and 5 wt% PVP. Dielectric and electrical properties were studied over 10(2)-10(6) Hz at room temperature, while DC transport was examined between 293.15 and 378.15 K. The dielectric constant decreased with increasing frequency. At 1 MHz and 25 wt% TiO2, epsilon ' increased from 6.43 for anatase to 8.57 for rutile, while dielectric loss decreased from 0.061 to 0.046. The highest AC conductivity was observed at 20 wt% TiO2, reaching 1.0 & times; 10(-4) and 8.6 & times; 10(-5) S m(-1) for the 400 and 700 degrees C series, respectively. DC conductivity increased with temperature, and activation energy decreased from 0.65 eV for the polymer blend to 0.128-0.087 eV at 25 wt% TiO2. These results highlight the potential of the prepared membranes for dielectric and electrical insulation applications.
A novel strategy is proposed to enhance the performance of styrene-butadiene rubber (SBR) by constructing a hybrid filler network comprising graphene (GE) and helical carbon nanofibers (HCNFs). In this study, SiO2/GE/HCNFs/SBR composites were prepared via a two-step "wet masterbatch-dry blending" process. The results demonstrate that GE and HCNFs exhibit complementary effects in geometric morphology and mechanical properties. Optimal comprehensive performance was achieved at a GE:HCNFs mass ratio of 1:2 (total filler loading of 2 phr). Compared with the pure SiO2 compound, the tensile strength increased by 30.6 %, tear strength improved by 29.4 %, abrasion loss volume decreased by 25.9 %, and the elongation at break remained above 530 %. At this optimal ratio, the loss factor (tan delta) at 60 degrees C decreased by 10.8 %, whereas no significant reduction was observed at 0 degrees C, thereby achieving an excellent balance between low rolling resistance and wet traction. Quantitative analysis revealed that the synergistic contribution of HCNFs and GE reached as high as 53.5 %. This study achieved efficient reinforcement of SBR at ultra-low filler loadings through a rationally designed GE/HCNFs hybrid system, offering an innovative approach to breaking through the "Magic Triangle" bottleneck in tire materials.
Polyoxymethylene (POM) and polyamide 66 (PA66) exhibit extensive utilization in gear systems owing to their superior self-lubricating capabilities, elevated thermal stability, and favorable anti-frictional characteristics. As for metals, different mateal combinations can prevent abrasive wear because of small surface energy. How is the tribological properties of POM combined with PA66? In this study, the influence of PV value on the tribological properties of PA66 and POM are researched by using a pin-on-disk friction test device. The result shows that under high PV conditions, the friction coefficient and wear rate of the PA66-POM and POM-PA66 sliding combinations are consistently lower than those of POM-POM and PA66-PA66 due to the transfer film layer which effectively reduces the impact of friction heat on the contact surface. In addition, the wear mechanism of PA66-PA66 and POM-POM sliding combinations is mainly adhesive wear, whereas the wear mechanism of PA66-POM and POM-PA66 sliding combinations is abrasive wear and adhesive wear. For the PA66-POM and POM-PA66 sliding combination, grease destroys the formation of the transfer film, which increases the wear rate at high PV values.
Polyethylene oxide (PEO) exhibits excellent segmental flexibility and solubility for lithium salts, but its high crystallinity at room temperature results in relatively low ionic conductivity. To enhance its performance, this study incorporates highly adsorbent fibrous sepiolite (SEP) and zeolite imidazolate framework (ZIF-8) with high specific surface area and tunable pore structure. These are combined into a ZIF-8@SEP filler, aiming to synergistically reduce PEO crystallinity and establish rapid ion transport pathways. A series of PEO-based composite electrolyte films were prepared via the casting method and assembled into button cells for testing. The results demonstrate a significant improvement in ionic conductivity, reaching up to 6 & times; 10-5 S cm-1 at 60 degrees C. This study provides new insights for developing safe and efficient composite solid-state electrolytes.
The performance of polymeric thin-film composite (TFC) membranes is strongly influenced by fabrication parameters associated with both the polymeric porous support and the upper selective layer. The complex interactions among these parameters reduce the effectiveness of traditional experimental analyses. In this study, artificial neural network (ANN) models were developed to correlate key fabrication parameters of the support and polyvinyl alcohol (PVA) selective layer with the performance of PVA-based TFC membranes. Under the limited data size condition, a radial basis function (RBF) network was employed with leave-one-out cross-validation (LOOCV) to optimize the model and improve its reliability. The models demonstrated high predictive accuracy, with R-2 values of 0.9923 for permeability and 0.9986 for salt rejection. A reduced-dimension ANN (R-ANN) was further implemented by statistically screening the input variables, which improved model efficiency while maintaining high accuracy. Analysis of key fabrication parameters revealed that cross-linking the PVA layer with a cross-linking agent and heat curing critically influenced salt rejection, which exhibited complex nonlinear behavior in relation to other fabrication parameters. The proposed ANN successfully identified these nonlinear trends by considering the co-effects of multiple parameters. Although predictive capability is limited for unseen conditions, ANN outputs were consistent across the examined parameter range.
Industrial wastewater containing methylene blue (MB) poses major environmental and health risks due to its persistence, toxicity, and resistance to biodegradation, necessitating more efficient treatment strategies. Conventional adsorption and photocatalysis methods often suffer from limited recyclability, low recovery, and reduced overall efficiency, driving interest in nanomaterial-based solutions. This study aims to improve adsorption-photocatalytic degradation of MB using cellulose acetate (CA) electrospun nanofiber membranes modified with graphene oxide (GO), metal oxides (ZnO, TiO2, CdS), and zeolite. The membranes were fabricated via electrospinning and characterized using FESEM, EDX, XRD, Raman spectroscopy, and FTIR to determine morphology, composition, crystallinity, and functional groups. Adsorption-photocatalytic performance was analyzed by UV-Vis spectroscopy, with Langmuir and Freundlich models used to evaluate adsorption behavior. The CA/SDS-GO/zeolite/TiO2 membrane nanofiber achieved the highest performance, with an adsorption-photocatalysis capacity of 233.20 mg/g and efficiency of 93.28 %, outperforming ZnO- and CdS-based variants. Its superior activity is attributed to increased surface area, enhanced porosity, and strong synergistic interactions with TiO2. The adsorption data followed the Langmuir isotherm model (R-2 = 0.9999), indicating monolayer adsorption with high dye affinity. These findings highlight the potential of GO-metal oxide-zeolite nanocomposites as effective, environmentally friendly materials for wastewater treatment.
We developed a degradable pluronic F-127 (PF-127)-based drug delivery system-poly(ethylene glycol)block-poly(propylene glycol)-block-poly(ethylene glycol)-to localize STS and control its release directly at the target vein. The characteristics of the STS-loaded depot were assessed, and in vitro release profiles were quantified by high-performance liquid chromatography (HPLC). The in vivo elution behavior of STS from PF-127 was further evaluated in a rabbit vein model by administering equal doses of STS either as free drug or formulated within PF-127. This novel sustained-delivery approach provided continuous STS release for more than 14 days in vitro and achieved prolonged, high local STS levels in the rabbit ear vein for up to 28 days, while keeping systemic concentrations low. In addition, the PF-127-based drug delivery system significantly attenuated the initial burst release observed with free STS, indicating a more controlled pharmacokinetic profile. Collectively, these quantitative findings show that the PF-127-based system adds clear value over free STS by extending local exposure, reducing peak-driven losses and off-target exposure, and potentially improving therapeutic durability for the treatment of varicose veins.
The growing environmental pollution from airborne particulates and oily wastewater has created an urgent need for advanced multifunctional filtration materials. The study evaluates electrospun polyacrylonitrile/activated carbon (PAN/AC) nanofiber membranes developed as dual-purpose filters for air-purification and oil-water separation. PAN solutions containing 5 %, 10 %, and 15 % AC were electrospun under optimized conditions. Among them, the PAN/10 % AC membrane exhibited the most uniform nanofiber morphology with an average diameter of 495-500 nm and the highest porosity (86.99 %) determined by mercury intrusion porosimetry (MIP), while maintaining structural stability. The addition of AC to PAN solutions resulted in better thermal stability according to thermogravimetric analysis (TGA) while tensile tests showed PAN/10 % AC achieved maximum mechanical strength at 2.907 MPa with 33.45 % elongation because of effective AC distribution and polymer-filler bond formation. The PAN/10 % AC membrane showed exceptional PM2.5 filtration performance with 99.29 % removal efficiency and 589.3 Pa pressure drop while achieving a QF of 0.0084 Pa-1. Additionally, the membrane exhibited strong hydrophobic proporties, resisting water penetration for over 10 min, while showing rapid diesel oil permeation due to its oleophilic nature. Overall, the PAN/10 % AC membrane exhibits an optimal balance of structural, mechanical, and functional properties for environmental remediation applications, particularly high-performance air filtration and oil-water separation.
Ion imprinted polymers (IIPs) are polymeric materials that possess specific recognition cavities capable of selectively binding target ions. This study aims to synthesize Cd2+-based IIPs as selective adsorbents for cadmium ions. The synthesis was carried out using Cd(NO3)(2)& centerdot;4H(2)O as the template ion, MAA as the functional monomer, EGDMA as the crosslinker, and DMPP as the initiator. The synthesized IIPs were characterized using FTIR. The FTIR spectrum shows a difference in the C-O absorption band, namely 1,144.75 cm(-1) on NIP and 1,145.41 cm(-1) on IIPs-Cd. Then, the C-O absorption band shifted to 1,144.05 cm(-1) when Cd was extracted from IIPs-Cd, but the absorption band reappeared at 1,144.72 cm(-1) after Cd2+ rebinding, which indicated the presence of Cd-O coordination interaction and confirmed that the printing process was successful. The highest adsorption capacity was achieved at an MAA: EGDMA ratio of 1 mmol:4 mmol, pH 4, an extraction time of 60 min, a contact time of 30 min, and an initial Cd2+ concentration of 25 mg/L, yielding a maximum adsorption capacity of 0.6528 mg/g. The adsorption process followed the Langmuir isotherm model with an R-2 value of 0.9551 and exhibited high selectivity toward Cd2+ compared to competing ions Zn2+, Cu2+, and Pb2+.
