Journal of Polymer Research最新文献

The development of novel semi-IPN hydrogels composed of a cross-linked chitosan (CC) network and a thermo-responsive linear copolymer, i.e., poly (N-isopropyl acrylamide-co-acrylic acid) [P(NIPAM-co-AA)], with drug release capability in response to both temperature and pH changes has various potential medical applications. The thermo-responsive free copolymer chains inside the CC network were synthesized via free-radical polymerization to prepare the thermal and pH dual-responsive P(NIPAM-co-AA)/CC hydrogels with a semi-IPN structure. The prepared copolymers and semi-IPN hydrogels were characterized by FTIR, TGA, ¹H and ¹³C NMR apparatus, and the LCST transition was determined using UV/Vis spectroscopy. The stronger C-H stretching of the semi-IPN sample at 2920 cm⁻¹ than the CC sample showed that the NIPAM and AA monomers successfully polymerized inside the CC network structure. TGA analysis of the semi-IPN sample exhibited peaks at 249, 379, and 290 °C, corresponding to the presence of the thermo-responsive copolymer composition and the chitosan polymer, respectively. The results showed that depending on the temperature below and above the LCST, the semi-IPN hydrogel exhibited a lower (194%) and higher swelling percentage (413%) because the copolymer chain conformation changed from the coil to globule. The drug release results implied that above the LCST, the hydrogen bond between the gallic acid molecules (GA, drug model) and the semi-IPN structure may be broken, causing a change in drug release in the range of 4.5 − 39.1%. The anti-bacterial test and cytotoxicity of the selected semi-IPN sample were carried out. In an MTT assay, the highest cell viability of the semi-IPN sample with 7.5 mg/ml at 37 °C was 4% more than the control group. The semi-IPN containing GA exhibited anti-bacterial action against the S aureus bacterial strain significantly. This research describes a method to prepare a smart dual-responsive semi-IPN structure with a potential for transdermal applications.

The composition of a new powder epoxy-benzoxazine polymer using epoxy resin DER671 and benzoxazine BA-a obtained from bisphenol A and aniline has been developed. Sheets of vacuum-bag-only (VBO) dry prepregs were obtained by applying a polymer powder in an electrostatic field to a carbon fiber and subsequent vitrification. The optimal composition of the epoxy-benzoxazine polymer (benzoxazine 50 mas%) and its curing mode (180° C—60 min, 220° C—60 min) were established by the methods of DSC, rheology and DMA. A high wettability of carbon fibers with a molten polymer was found, while voids between the yarns remain free. Consolidated plates obtained from VBO dry prepregs have low porosity and high volume fiber content (57.5 ± 1.3%). A test product in the geometry of a double dome, characterized by the absence of defects was obtained according to the selected modes by compression molding from a consolidated plate.

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In this article, erythritol tetranonanoate (ETNT), synthesized through erythritol extracted from agro-food industry waste through various green processes with nonanoic acid, as the saccharide-based plasticizer, is applied to starch to prepare thermoplastic starch (TPS). A series of biodegradable PBS blends are fabricated through the melt blending with TPS and Glycidyl methacrylate (GMA) grafted poly (butylene adipate-co-terephthalate) (PBAT), namely PBAT-g-GMA, in an attempt to simultaneously enhance the toughness and stiffness of the result materials. In this work, the resulting biodegradable PBS blends are in detail studied from the perspectives of mechanics, thermal properties, rheology, crystallization and morphology. The structure of ETNT is confirmed by Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance (¹H NMR). Incorporating 50 wt% TPS into the blends results in a remarkable increase of 125% in the Izod impact strength and 18% in the Young’s modulus compared to pure PBS, demonstrating that our proposed strategy is efficient for preparing PBS blends with good comprehensive properties through a straightforward, environmentally friendly, and cost-effective processing method. The DSC result indicates that the addition of TPS at 50% leads to a crystallinity of 24.1% in the blends, which is 66.1% lower than that of PBS. Rheological analysis reveals that the storage modulus (G'), loss modulus (G"), and complex viscosity increase significantly with higher amounts of PBAT-g-GMA and TPS, indicating improved processability. SEM shows that the addition of PBAT-g-GMA progressively homogenizes the blends and enhances the bonding between TPS and the matrix.

Self-healing materials have gained significant attention due to their ability to autonomously repair damage, extending material lifespan. In this study, bio-based self-healing polyurethanes were synthesized using modified castor oil (MCO) as the soft segment and 5-(2-hydroxyethyl)- 6-methyl- 2-aminouracil (UPY) and 2,2'-diaminodiphenyldisulfide (DTDA) as dynamic components. The synergistic effect of quadruple hydrogen bonding and disulfide bonds was investigated by varying the n(UPY)/n(DTDA) ratio. Structural and mechanical properties were characterized using IR, DSC, TGA, XRD, and tensile testing. The results revealed that the castor oil-based polyurethanes exhibited transparency and amorphous structures, making them promising bio-based self-healing materials. When the DTDA content was 9.54% and the UPY content was 1.62%, the material achieved a self-healing efficiency of 96.38% under 80 °C for 12 h. Additionally, at a DTDA content of 6.65% and a UPY content of 2.43%, the tensile strength reached 17.76 MPa. Mechanistic analysis revealed that disulfide bonds played a dominant role in self-healing, while hydrogen bonds provided additional reinforcement. This work presents a novel bio-based polyurethane system with tunable mechanical and self-healing properties, contributing to the development of sustainable smart materials.

The traditional artificial leathers were produced by wet process. In this process, organic solvent DMF was needed to employ large amounts of water and DMF, which caused serious environmental pollution and consumed a lot of energy for the recycling solvent process. This study used sustainable solvent-free waterborne polyurethane (SFWPU), an eco-friendly foam coating to replace DMF wet-process PU leather products without using a large amount of DMF and solvent-treating equipment to keep from high energy consumption. This study addresses the optimization of solvent-free waterborne flexible polyurethane (FPU) foams obtained from polyols with different chemical structures and hydrophilic group contents based on the foam ratio and abrasion resistance. For this purpose, the study adopted a patented prepolymer process to synthesize SFWPU, which was subsequently expanded to foam by using a physical blowing agent. Diverse polyol with ether, ester, and carbonate types and hydrophilic contents synthesize a series of SFWPUs. These strategies are mainly focused on the foam ratio, mechanical properties, foam structure, and abrasion resistance of FPU foams. This study showed that polyol type did not significantly affect the foam ratio. However, scanning electron microscopy revealed that the foam cells on the ether and carbonate types of the FPU foams were increasingly smaller. For this reason, the carbonate diol and ether diol of FPU foams have better abrasion resistance than ester-type polyols of FPU foam. The hydrophilicity of the foam affects the foam ratio, mechanical properties, foam cell, and abrasion resistance. The 5 wt.% hydrophilic content of carbonate-type FPU foam has better abrasion resistance, which is only 0.25 w.t.% weight loss after the Taber abrasion test. An adequate combination of these components leads to better abrasion resistance and an appropriate foam ratio, which can replace DMF wet process PU leather.

This study focuses on enhancing the performance of polyvinylidene fluoride (PVDF) membranes through a straightforward and cost-effective modification process. Multi-walled carbon nanotubes (MWCNTs) and adsorbed polyacrylic acid (PAA) were introduced onto the membrane surfaces, resulting in modified substances (P-MWCNTs) that improved compatibility with solvents. Subsequently, the PVDF membrane surfaces were patterned using an embosser to evaluate the effects of this modification. The results revealed that the modified membranes in group C5 (15% PVDF, 0.40% MWCNTs, 3% PAA, 25 μm imprinting depth) achieved optimal performance, exhibiting a flux of 915.47 L/(m²·h), a retention rate of 93.37%, and a reduced contact angle of 47.9°. This patterned surface modification significantly enhanced retention performance, flux, and fouling resistance of the PVDF membranes, contributing to improved treatment efficacy and longevity, thus presenting promising application prospects.

This study focuses on the synthesis and characterization of copolymers derived from mustard oil-based erucic acid macromer and methyl methacrylate (MMA) monomer. A series of copolymers were synthesized by varying the ratio of macromer and monomer via free radical polymerization. The structure of obtained copolymers was analyzed by FTIR and ¹H-NMR spectroscopy. The TGA analysis of prepared samples exhibited multiple degradation stages and provided insights into the pyrolysis temperature of copolymers. Also, thermal stability was enhanced with an increase in alkyd content. Glass transition temperatures (T_g) of copolymers were measured using DSC. The SEM images show the changes in porosity with variations in the monomer ratio, reflecting the influence of alkyd and acrylate content on the material surface. XRD reveals the amorphous nature of the copolymers. The objective of the copolymerization process was to enhance the thermal stability and other physico-mechanical properties of the copolymers. Various tests were conducted to evaluate the performance of the copolymers as coating materials, including water and chemical resistance, adhesion, pencil hardness, and drying time. The results revealed that the incorporation of MMA into the alkyd improved the alkaline resistance and water resistance behavior of the copolymer. Overall, this study showcases the potential of copolymers derived from alkyd and MMA for diverse applications, especially in coating materials with improved properties to withstand challenging conditions.

Graphical Abstract

Improving the specific capacitance of electrochemical double layer capacitors (EDLCs) is a critical but challenging research goal. High ionic conductivity electrolytes are essential materials in current EDLC technology. In present work, glycerol was incorporated as a plasticizer into a zein-honey-NH₄NO₃ based gel polymer electrolyte (GPE) to enhance the properties of the electrolytes. The zein-honey-NH₄NO₃ GPE (ZHNG10), containing 10 wt.% glycerol demonstrated the highest ionic conductivity of (1.00 ± 0.79) × 10^–2 S cm⁻¹ at room temperature. ZHNG10 also exhibited the lowest degree of crystallinity (12.195%) and a crystallite size of 2.185 nm, indicating a predominantly amorphous structure that facilitates ion conduction. Morphology analysis revealed a porous structure in ZHNG10, promoting continuous pathways for H⁺ ion movement, with an increase in ions density (n), mobility of ions (µ), and diffusion coefficients (D) upon 10 wt.% glycerol addition. Transference number measurement (TNM), indicated an ion transference number 0.99, showing that ions are the dominant charge carriers. ZHNG10 was electrochemically stable up to 2.99 V, indicating safe of the EDLC up to 2.0 V. The specific capacitance (C_sp) of the single-electrode-based EDLC was 196.61 F g⁻¹ based on cyclic voltammetry (CV) and 345.38 F g⁻¹ based on charge–discharge measurements, with an efficiency of more than 90%.

Biopolymer composites used for biomedical applications can have forms ranging from soft viscoelastic gels used for 3D printing, to rigid scaffolds or films used for wound healing. We highlight the importance of multi-scale hierarchical structural morphologies on the tunability of mechanical response at different length scales, including tools for the characterization of this structure–function relationship. Detailed studies are presented which have shown how the addition of different fillers to the biopolymer matrix can modify mechanical response through structural changes. Tissues in the human body have mechanical strength ranging from millipascals to gigapascals, and non-linear viscoelasticity with strain-stiffening behavior. A comparison of mechanical properties of different types of cells and tissues is carried out with respect to fabricated biopolymer composites, as one of the factors regulating interfacial mechano-compatibility of implants and scaffolds. Cellular response is shown to be governed by the interfacial mechanobiology involving the biopolymer scaffold, extracellular matrix, and the tissue. Special focus is on guar-gum starch hydrogels (unpublished results) to show how matrix stiffness can regulate interfacial antimicrobial properties. Finally, the requirements for efficient and durable 3D printed biomedical constructs developed by the application of artificial intelligence tools are presented. Conducting polymer hydrogels for neurological implants and quantum dot – conducting polymer network hydrogels for biomedical applications are reviewed, with emphasis on factors regulating their efficiency.

This study comprehensively investigated the production of eco-friendly polyols through the in-situ epoxidation of castor oil, employing a hybrid kinetic modeling approach that combined Particle Swarm Optimization (PSO) and Simulated Annealing (SA). The epoxidation process was optimized using the Taguchi method, which identified stirring speed as the most significant process parameter, supported by a p-value of 0.000 and an F-value of 95.92. The reaction was carried out under optimized conditions, where 50 g of castor oil was reacted with hydrogen peroxide and acetic acid at a molar ratio of 1:1:1, a temperature of 65 °C, and a stirring speed of 200 rpm. The relative conversion of oxirane (RCO) was determined using the AOCS Official Method Cd- 957. As the reaction progressed, the near-zero RCO values confirmed complete hydroxylation. The epoxidized castor oil was then mixed with various hydroxylation reagents at epoxide-to-reagent molar ratios of 1:0.5, 1:1, and 1:1.5 to evaluate the hydroxylation rate. The results showed that all reagents achieved the fastest hydroxylation at the highest molar ratio of 1:1.5. The synthesized polyols were categorized based on their hydroxyl values, revealing that polyols produced using peracetic acid (79.3 mg KOH/g), water (85.0 mg KOH/g), and hydrogen peroxide (89.1 mg KOH/g) were suitable for flexible polyurethane applications. In contrast, polyols derived from methanol (127.9 mg KOH/g), acetic acid (139.4 mg KOH/g), and water (108.1 mg KOH/g) exhibited hydroxyl values between 100 and 250 mg KOH/g, making them more suitable for semi-rigid polyurethane applications. Kinetic parameters were determined through MATLAB R2023 A simulations, yielding reaction rate constants for key steps in the epoxidation and hydrolysis processes: k₁ = 0.03 M⁻¹ min⁻¹, k₂ = 0.00 M⁻¹ min⁻¹, k₃ = 30.00 M⁻¹ min⁻¹, and k₄ = 0.050 M⁻¹ min⁻¹. The hybrid PSO + SA simulation model demonstrated a strong correlation with experimental data, achieving an R² value of 0.9961, significantly outperforming the individual PSO model (0.9836) and SA model (0.9779).