Journal of Polymer Research最新文献

The aim of this work is to provide a simple tool for estimating the effective free radical polymerization rate constant and average chain length for multiphase systems when initiation occurs only at the phase boundary. Three cases are considered - polymerization of monomer layer, droplet and jet. The radical distribution profile was found for each geometry by approximating the solution of the appropriate diffusion-reaction problem in a limit of low and high Damköhler number. Averaging of corresponding profile over the system volume allows us to estimate expressions for effective rate constant and average chain length in terms of a Damköhler number. The expressions obtained in this way were shown to be in a good agreement with numerical calculations.

Additive manufacturing of short carbon fiber reinforced polymer composites (SCFRPC) is achieving attention as a growing fabrication technique for manufacturing complicated, greatly customizable designs parts. Short carbon fibers (SCF) have distinct characteristics such as excellent stiffness, strong tensile strength and resistant to corrosion as well as lightweight. The SCF feature a significant strength-to-weight and stiffness-to-weight proportion, making them an excellent choice for extreme strength applications. In this comprehensive review, we explore the additive manufacturing of the short carbon fiber with the various polymer’s matrix, processing parameters, interfacial bonding among the carbon fiber and matrix materials, and the challenges during manufacturing of the SCFRPC. The additive manufacturing of the SCF with the different polymer matrix materials printed at the different orientation of the fiber, and having the different volumes of the fiber content was presented. Furthermore, this review also highlighted the advantages and disadvantages of the SCF reinforced polymer composites and primary processing difficulties such as voids or gaps generation, anisotropic behavior, design limitations, and layer-by-layer appearance. Finally, it critically examined the obstacles and potential associated with SCFRPC manufacturing, which intends to assist stakeholders who wish to manufacture the SCF using the different polymers matrix with complete guidance.

In this paper, the preparation of a super absorbent polymer from bio-based monomer by free radical polymerization of tamarind kernel gum(TKG), itaconic acid (IA) in presence of kaolin powder with potassium persulfate (KPS) as reaction initiator and n-methylenebisacrylamide (n-MBA) as a cross-linker has been done. The reaction depends on the concentration of following variables like initiator, monomer, cross-linker, and kaolin. The optimization of swelling behaviour was done. In situ polymerization, hydrophilicity, stability and release kinetics were analysed. The FTIR gave the chemical composition by identifying functional group of the product structure by indicating specific frequency on Fourier Transform Infrared Spectroscopy. TGA was performed to investigate the weight loss to observe the thermal stability of synthesized superabsorbent polymer composite. The linkage of kaolin-organic monomer was seen at an absorption band of 2924 cm^− 1in the composite spectrum. The swelling behaviour measurements were analysed in diluted salt solution as well. It was observed that on increasing the concentration of n-MBA and kaolin the swelling capacity decreased.The swelling behaviour was also studied by varying pH to observe the response of composite towards pH. Swelling-Deswelling pulsation behaviour was recorded at pH 2 and 12. The swelling kinetics of synthesised composites with various porous sizes was also researched. Such characteristics make these smart materials suitable for several technological applications.

The paper presents a divergent synthesis of oligohydroxyethylaminoethyl carbonate via block co-oligocondensation of dimethyl carbonate and triethanolamine. Optimization of synthetic conditions (catalyst, reagent ratio, temperature) ensured high yields of the intermediate product (G0.5) and the final dendrimer (G1) – 99.5% and 98.91%, respectively; the Cu(II) complex was also obtained in 73% yield. The structure and properties of the compounds were confirmed by comprehensive physicochemical analysis (¹H and ¹³C NMR, IR, UV–VIS, TGA, X-ray diffraction). The morphology and particle size of the dendrimer agglomerates and its Cu(II) complex were studied by SEM, CLSM, NTA and DLS; The high stability of the dendrimer both in solution and in dry form was established, while the Cu(II) complex demonstrates a tendency to increase the size of the agglomerates after removal of the solvent, which opens up prospects for its application in optoelectronics and catalysis. Dendrimer improves the tanning of hare skins, increasing the strength and quality of the leather without reducing its technological properties.

To address the flammability, dense smoke emission, and fire safety concerns of epoxy resin (EP) in automotive components, this study develops a sulfur-free, multi-element reactive flame retardant (FA) integrating phosphorus, nitrogen, boron, and silicon. Synthesized from 4-formylphenylboronic acid, 3-aminopropyltriethoxysilane, and DOPO, FA enables a synergistic flame-retardant mechanism in EP. At a 2.5 wt% FA loading, the composite attained a UL-94 V-0 rating and displayed a limiting oxygen index of 29.1%, with complete suppression of dripping. Based on cone calorimeter measurements, the modified epoxy resin EP/FA7.5 exhibited significant reductions: a 41.4% decrease in peak heat release rate, a 27.7% decline in total heat release, and a 36.5% drop in cumulative smoke production. Crucially, the EP/FA7.5 composites meet the stringent EN45545-2 HL 1 smoke density standards (D_s(4) and VOF₄) and exhibit superior smoke suppression. FA promotes a dense char layer in the condensed phase and enhances mechanical properties: EP/FA5 exhibits a flexural strength of 103.6 MPa due to rigid aromatic interactions. This work presents a scalable strategy for fabricating fire-safe, high-performance epoxy composites demonstrating potential for application in fields requiring high fire safety, such as transportation and electronics.

This study presents the development and characterization of dual crosslinked xanthan gum–polyvinyl alcohol (XP) hydrogel films for potential use in controlled drug delivery applications. Hydrogel films were synthesized using glutaraldehyde for covalent crosslinking and Cu²⁺ ions for ionic crosslinking, with varying polymer ratios and crosslinker concentrations. The swelling behavior and gel content were evaluated in both distilled water at 25 °C and simulated body fluid (SBF) at 37 °C, revealing that dual crosslinking significantly enhanced structural integrity and swelling resistance, with gel content reaching up to 98%. Thermal analysis using DSC and DMA confirmed increased glass transition temperatures, indicating reduced polymer chain mobility due to denser crosslinking networks. Mechanical tests showed that the films possessed high tensile strength (60–62 MPa), with stiffness increasing alongside Cu²⁺ concentration and xanthan content. Cytocompatibility was validated through MTT assays on Vero cells, with all formulations exceeding 80% viability, thus classified as non-cytotoxic according to ISO 10993-5:2009 guidelines. Drug release studies using para-acetylaminophenol demonstrated sustained release behavior, achieving 50% release over 6 h in SBF. Kinetic analysis revealed that the release followed zero-order kinetics (R² = 0.9986) and case-II transport (n = 1.0396), indicating that release was governed by matrix swelling and erosion. These findings highlight the potential of XP dual crosslinked hydrogels as effective and biocompatible platforms for sustained drug delivery, particularly in wound care applications.

The current study investigates the synergistic role of styrene monomer (St) in enhancing the grafting efficiency of the maleic anhydride on the linear low-density polyethylene (LLDPE), focusing on the interfacial adhesion strength in tie layer adhesives. The MA was grafted onto the polyethylene backbone using dicumyl peroxide (DCP) initiator and evaluated in terms of grafting degree regarding the DCP concentration, MA concentration, and styrene monomer incorporation. The results indicated that the amount of initiator and MA directly influences the grafting degree in the reaction, so an optimum amount is preferred. Furthermore, the incorporation of styrene significantly improves grafting efficiency, hydrophilicity, and mechanical performance. Here, the highest MA grafting degree was obtained at about 1.12% using 0.5 wt% DCP and incorporating 3 wt% styrene monomer. T-peel tests confirmed that the adhesive strength increased with a grafting degree and tie layer thickness. The results proved the effectiveness of styrene monomer on the maleic anhydride grafting degree on and tie layer interfacial adhesion styrene.

Sodium poly(4-methacryloylaminosalicylic acid) was synthesized by classical radical polymerization and studied by molecular hydrodynamics methods in dilute salt-free, salt and alkaline solutions in a 20-fold range of MM. The features of macromolecule compaction in solvents of different compositions, in which the sizes of macromolecules change more than 100 times, were considered. Molecular characteristics and the scaling relations [η] = (1.5 ± 0.1)×10^–3×M^0.86±0.01, s₀= (4.5 ± 0.4)×10^–15×M^0.41±0.02, D₀ = (3.2 ± 0.3)×10^–4×M^{–0.59±0.01} were obtained in 0.1 M NaCl + 0.1 M NaOH. The Kuhn segment of the molecules was estimated using two consimilar and cognate methods – Gray–Bloomfield–Hearst theory and the software Multi-HYDFIT. A comparison with other macromolecular structures of vinyl series was made.

Graphical abstract

Poly (m-phenylene isophthalamide) (PMIA) is a highly significant aromatic polyamide known for its excellent mechanical strength, high thermal stability, chemical resistance, and electrical insulating properties. PMIA finds extensive applications in areas such as filtration membranes, electronic device separators, fire-resistant textiles, and high-performance composites. In this study, PMIA was synthesized via interfacial polycondensation between m-phenylenediamine (MPD) dissolved in water and isophthaloyl chloride (IPC) dissolved in tetrahydrofuran (THF). The effects of key reaction parameters, including temperature, reaction time, stirring rate, monomer concentration and ratio, acid acceptor, and solvent type, on the intrinsic viscosity and yield of PMIA were systematically investigated. Optimized conditions yielded PMIA with a high molecular weight, evidenced by an intrinsic viscosity of 2.1 dL/g and an excellent yield of 99.7%. The resulting polymer demonstrated a tensile strength of 25 MPa, an initial degradation temperature of 440 °C, and a dielectric constant of 3.44 at 1 Hz. These results confirm that PMIA synthesized by interfacial polycondensation possesses outstanding thermal resistance, mechanical performance, and electrical properties, making it highly attractive for advanced material applications. These results establish a route to tailor high-performance PMIA via interfacial polycondensation, with potential for scalable applications in advanced electronics and insulation technologies.