Journal of Polymer Research最新文献

Polyacrylonitrile (PAN) nanofiber skeleton has become essential components in designing high-performance composite materials such as solid electrolytes, however, its widespread application is still limited by high flammability. In this work, phytic acid-modified mesoporous silica (PA-mSiO₂) was prepared via the sol-gel method followed by surface modification, and then it was incorporated together with a phenethyl-bridged DOPO derivative (DiDOPO) into a PAN precursor solution to fabricate composite nanofibers via electrospinning. The morphology and structure of the prepared PA-mSiO₂ and the resulting composite nanofiber skeleton were characterized. The flame retardancy of the PAN composite nanofiber skeleton was evaluated, which revealing a pronounced synergistic effect between PA-mSiO₂ and the DOPO derivative. The combined system was more effective than the individual additives in suppressing combustion, as evidenced by reductions in the peak heat release rate (pHRR) and total heat release (THR) by 34.5% and 12.7% respectively, along with increases in the limiting oxygen index (LOI) and char yield by 52.5% and 18.1% respectively. The synergistic mechanism was investigated, indicating that PA-mSiO₂ primarily acted in the condensed phase by catalyzing the formation of a stable, phosphorus-rich siliconaceous char layer that acted as a thermal barrier. Simultaneously, the DiDOPO derivative functioned in the gas phase by releasing flame-inhibiting radicals. This work demonstrates an effective strategy for creating flame-retardant PAN nanofiber skeleton, which may hold potential for application in high-safety electrolyte design.

This study investigated the fabrication of sodium alginate (SA) microparticles embedded in polyvinyl alcohol (PVA) hydrogel for tissue regeneration applications. The combination of SA and PVA produces composite hydrogels with enhanced mechanical performance and tunable degradation behavior. SA microparticles were incorporated into a PVA matrix using a freeze–thaw technique to form composite hydrogel scaffolds. The physicochemical and mechanical properties of the scaffolds were systematically evaluated to determine their suitability for wound healing applications. The results of this study provide significant information about the potential of SA microparticles embedded in PVA hydrogel for wound healing. Incorporation of SA microparticles enhanced the physicochemical and mechanical properties of the hydrogel, while reducing the water vapor transmission rate (WVTR) without significantly affecting moisture content compared to pure PVA hydrogel. These findings indicate that the SA/PVA composite hydrogel exhibits favorable physicochemical and mechanical characteristics for potential use as a wound dressing material.

MXD6 (poly(m-xylylene adipamide)), as a semi-aromatic polyamide, is extensively utilized in packaging, automotive, and unmanned aerial vehicle fields. High strength and heat resistance are very important properties for an engineering plastic. To enhance the thermal and mechanical properties of MXD6, in this study, we investigated the influence of aromatic dicarboxylic acids on its copolymerization. MXD6 and its copolymer derivatives were synthesized via a one-pot synthesis method, which only takes six and a half hours, and the chemical structures of the resulting copolymers were characterized using Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) test results indicated that the crystallinity gradually decreased with the introduction of MXDT and MXDI segments. Differential scanning calorimetry (DSC) results demonstrated that the incorporation of copoly(aromatic dicarboxylic acid) segments led to an increase in the glass transition temperature (Tg). Specifically, the Tg of the samples containing 10% MXDT and MXDI segments rose from 77.6 °C to 91.4 °C and 82.4 °C, respectively. Thermogravimetric analysis (TGA) results indicated that the copolymer aromatic dicarboxylic acid would lower the initial decomposition temperature, but expand the decomposition temperature range. The results of the heat distortion temperature (HDT) test showed that the introduction of MXDT and MXDI segments would increase the heat distortion temperature of MXD6, and the increase was more obvious when MXDT segments were introduced compared to MXDI segments. Specifically, when the content of MXDT segments reaches 20%, the heat deflection temperature of MXD6‑T reaches 80.5 °C, which represents an increase of 13.3 °C relative to that of the pristine MXD6 sample. The mechanical property test results indicated that the tensile and flexural properties presented a trend of increasing first and then decreasing, and the introduction of 10% aromatic dicarboxylic acid was the best, while the impact performance decreased. The findings confirm that the inclusion of aromatic dicarboxylic acid segments enhances the heat resistance performance of MXD6. The copolymer with 10% aromatic dicarboxylic acid content shows optimal mechanical performance, establishing this formulation as the most effective. Owing to the fact that this study involved only two types of aromatic dicarboxylic acids in the copolymerization, the aforementioned conclusions are consequently of a relative and context-dependent nature.

Sustainable multifunctional composites derived from waste biomass and silica are under intense investigation for wastewater remediation owing to their economic and environmental advantages. In the current study, Cellulose nanofibers (CNF) were prepared via the TEMPO-mediated oxidation process, and (3-Aminopropyl)triethoxysilane (APTES) was used as a silica precursor for surface modification of the fibers. The CNF/silica–NH₂/Ag-NPs composite polymer was characterized by SEM, TEM, TGA, and FT-IR, confirming its successful formation. SEM investigation exhabit bright, well-dispersed spots observed in the SEM images correspond to Ag-NPs embedded within the porous CNF/silica matrix. TEM analysis showed a non-uniform coating of amorphous, spherical silica particles with an average size of ~ 25 nm for Ag-NPs. The developed CNF/silica–NH₂/Ag-NPs composite polymer was evaluated as a multifunctional material for the removal of both cationic and anionic dyes, as well as for its antimicrobial activity against pathogenic microorganisms. The bioadsorbent showed better removal efficiency for methylene blue (MB) and methyl orange (MO) dyes due to electrostatic attraction. From the isotherm studies, the Langmuir isotherm model provided the best fit, and CNF/silica-NH₂/Ag composite polymer displayed maximum adsorption capacities of 370 mg/g and 151 mg/g for MB and MO, respectively. From the reusability studies, it was observed that the multifunctional cellulose adsorbent exhibited appreciable adsorption values even after 5 cycles adsorption-desorption. The antimicrobial potential of the synthesized composite polymer showed different inhibition zone against Escherichia coli (18 mm), Salmonella typhimurium (20 mm), Staphylococcus aureus (16 mm), Streptococcus mutans (17 mm), and Candida albicans (15 mm). The findings revealed that the CNF/Silica-NH₂/Ag-NPs composite polymer exhibited vigorous antimicrobial activity against all tested pathogens, with minimum inhibitory concentrations (MICs) as low as 0.0012 mg/mL. Among them, E. coli demonstrated the highest MIC of 0.04 mg/mL, indicating relatively lower sensitivity to the composite polymer.

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In this study, the thermodynamic properties of agar were examined by the inverse gas chromatography method. The dispersive surface energy, (:{gamma:}_{S}^{D}) of the adsorbent was determined using the Schultz, Dorris–Gray, Donnet–Park, and Hamieh methods in the temperature range of 303.2–328.2 K. To evaluate the polymer-solvent interaction parameters, the specific retention volume of the solvents, (:{V}_{g}^{0}) values were determined using various nonpolar and polar solvents in the temperature range of 373.2–398.2 K. Then, from these data, the values ​​of the Flory-Huggins theory polymer-solvent interaction parameters, (:{chi:}_{12}^{infty:}), equation of state theory, polymer-solvent interaction parameters, (:{chi:}_{12}^{*}), effective exchange energy parameters, (:{X}_{eff}) and solubility parameter of agar, (:{delta:}_{2}) were calculated. Additionally, the isomer separation power of agar, (:{alpha:}_{A}) was assessed with selected isomer pairs in the temperature range of 303.2–333.2 K.

In this study, the Electro-assisted Solution Blow Spinning (E-SBS) process was optimized by the response surface method (RSM), and the diameter and pore size regulation mechanisms of PVDF and PA66 nanofiber membranes were systematically explored. Through single-factor experiments and RSM analysis, the influences of four process parameters - solution concentration, air pressure, voltage and solution push speed - on fiber diameter and uniformity were clarified, and an effective model was established. Experimental verification shows that the fiber diameter can be controlled between 0.06 and 0.16 μm in PVDF membranes and between 0.25 and 0.41 μm in PA66 membranes. Then, by controlling the diameters of PVDF and PA66 fibers and the weight of the fiber membranes, we explored the regulation of the pore size of the fiber membranes. The influence of three factors on the pore size of fiber membranes was studied by RSM, and the corresponding models were established. Experimental verification shows that the pore size of the fiber membrane can be adjusted within the range of 7.2 to 16.7 μm. Subsequently, the influence of different pore sizes on the filtration performance of fiber membranes was also discussed. It was found that when the pore size was 12 μm, the quality factor was the largest, reaching 0.06 Pa⁻¹, demonstrating excellent filtration performance. This study provides a theoretical basis for the optimization of the E-SBS process and offers new ideas for the design and application of nanofiber membranes.

Magnetic and photocatalytic composite particles of m-poly[EGDMA-1-VIM]@WO₃ were synthesized via suspension polymerization using Ethyleneglycoldimethacrylate and 1-Vinylimidazole. These particles were designed to remove Reactive Black 5 dye from textile wastewater through adsorption and photocatalytic decolorization. FTIR, XRD, ESR, BET and SEM–EDS elemental mapping analyses were performed to characterize the synthesized polymer composite particles. In adsorption studies, effect of pH, time, adsorbent dosage, temperature and initial dye concentration on capacity were evaluated. Although the increasing the temperature positively influenced the adsorption capacity, a higher amount of polymer had a negative effect. The experimental results aligned well with the Langmuir adsorption isotherm and the pseudo-second-order kinetic model and the thermodynamic parameters were calculated. For the decolorization process of the unadsorbed dye remaining in solution, the effects of time, adsorbent dosage, and dye concentration were investigated, and the decolorization kinetics were elucidated. It was found that under conditions of low dye concentration and high adsorbent dosage, the photocatalytic effect was optimal. Furthermore, the kinetics of decolorization were found to be in accordance with the Langmuir–Hinshelwood model. Highlights A completely new adsorbent, m-poly[EGDMA-1-VIM]@WO₃ polymer matrix composite particles with magnetic and photocatalytic properties were synthesised by suspension polymerisation method. FTIR, XRD, ESR, BET and SEM–EDX elemental mapping analyses were carried out to characterise the synthesised m-poly[EGDMA-1-VIM]@WO₃ particles. Adsorption processes were carried out. Adsorption isotherms and kinetic parameters were calculated. Photocatalytic decolouration processes were carried out. Decolorization kinetics were elucidated. The photocatalytic decolorization kinetics were consistent with the L–H model. The optimum result was 97.81% removal at 30 mg. L⁻¹ RB5 concentration.

A series of PDMAEMA-TPE copolymers with temperature and pH due-responsive AIE properties were synthesized by free radical copolymerization of N,N-dimethylaminoethylmethacrylate (DMAEMA) and tetraphenylethylene (TPE) monomer. It was found that PDMAEMA-TPE copolymers in alkaline aqueous solution have pH-dependent thermosensitivity with lower critical solution temperature (LCST). The LCST of the copolymers decreases with increasing both pH and the molar content of hydrophobic TPE units in the copolymers. The copolymers exhibit typical AIE behavior in aqueous solution. Temperature-dependent fluorescence shows an approximate two-fold increase in fluorescence intensity above the LCST. pH-dependent fluorescence presents that the fluorescent intensity of the copolymers increases with increasing pH. Particularly, there is a doubling increase in fluorescent intensity above pH 9.12. Both intra-aggregate contraction and inter-aggregates’ association controlled by temperature and pH are favored to the enhanced fluorescence emission of the PDMAEMA-TPE copolymers.

In this study, a novel plant-based shape memory biocomposite was developed for sustainable food packaging applications. A poly(lactic acid)/poly(hydroxyalkanoate) (PLA/PHA) blend was reinforced with the ethanolic extract of Moluccella spinosa, a plant recognized for its bioactive constituents. Structural and thermal analyses confirmed the successful incorporation of the extract without compromising the polymer matrix integrity. The results demonstrated improved barrier performance, characterized by lower water vapor permeability, reduced moisture content, and slightly increased opacity with increasing concentrations of M. spinosa extract. In addition, the composite films exhibited enhanced shape memory behavior, which became more pronounced at higher extract concentrations. Antimicrobial assays revealed a limited and selective inhibitory effect, primarily against Gram-positive bacteria (Enterococcus faecalis and Clostridium perfringens), while no notable activity was observed against Escherichia coli and Staphylococcus aureus. These findings indicate a preliminary antimicrobial potential, likely associated with a sustained-release mechanism rather than strong bactericidal activity. Overall, the integration of M. spinosa extract into the PLA/PHA matrix offers a promising route to design multifunctional, biodegradable packaging materials with shape memory capability, where antimicrobial functionality serves as a complementary feature, contributing to the advancement of environmentally friendly and active food packaging technologies.

The current study explores the effect of viscosity on cyclic nanoindentation response and the determination of stiffness (S), hardness (H), and reduced elastic modulus (E_r) for polycarbonate (PC) and poly(methyl methacrylate) (PMMA). Multi-cycle indentations were performed under before-hold and after-hold conditions up to 9000 µN. Both polymers exhibited pronounced hysteresis loops, with loop area increasing exponentially with cycle number. The fractional increment in loop area approached unity (~ 1.0), indicating stabilization of viscous energy dissipation. Creep during the hold phase decreased with increasing cycles, suggesting that most time-dependent deformation occurred during loading. S was calculated from the upper unloading segment to reduce viscoelastic effects. Due to a significant pile-up, the contact area was determined from residual imprints rather than the Oliver-Pharr method. Corrected E_r and H deviated by less than ± 5% from single-cycle results, keeping the H/E ratio, where E is elastic modulus, nearly constant. PC consistently showed higher H/E than PMMA, indicating greater resistance to plastic deformation and wear.