Journal of Polymer Research最新文献

Silica and carbon black fillers in Solution-based Styrene butadiene rubber (S-SBR) are investigated to improve tire performance for rolling resistance and traction under the influence of thermo-oxidative aging. This study provides a detailed analysis of the thermo-oxidative aging behavior in solution-styrene-butadiene rubber (S-SBR) compounds, a material extensively utilized in passenger car radial (PCR) tires. The performance of silica (Si), carbon black (CB), and Si/CB hybrid filler systems was investigated to assess their influence on aging resistance and mechanical durability. Comprehensive tensile testing, coupled with entanglement and crosslinking density analysis, revealed that silica-filled S-SBR compounds exhibit superior aging resistance compared to their carbon black and hybrid counterparts. Specifically, the Si-filled rubber (70 phr) demonstrated a significantly higher reinforcement index and a notably lower aging coefficient, suggesting enhanced retention of mechanical properties post-aging. Crosslink density increased markedly across all systems during thermo-oxidative aging, with Si-filled compounds outperforming CB and Si/CB-filled systems. The evolution of crosslink density and physical entanglements from polymer–filler, and filler-filler interaction was assessed using the Mooney-Rivlin model, which indicated that the Si-filled rubber showed the highest physical entanglement density upon aging. Interestingly, the Si-filled system also displayed a reverse stress-softening effect during aging, suggesting a complex interplay between filler–polymer interactions and entanglement dynamics. This behavior contrasts with the increased stress relaxation observed in CB-filled compounds, likely attributable to enhanced chain mobility and entanglement evolution. A schematic of polymer chain kinetics was proposed to elucidate the molecular-level interactions between the polymer matrix and filler systems during aging. Si-filled compounds exhibited elevated hysteresis and stress-softening resistance, confirming the superior aging performance attributed to silane coupling in silica-filled rubbers. These results underscore the potential of silica as a highly effective filler for improving the thermo-oxidative aging resistance of tire tread compounds, thereby offering valuable insights for developing high-performance, durable tire materials.

Thin and small low-frequency sound absorption structures have been an important research topic. In this paper, we combined the features of nanofiber membrane and micro-perforated structure to prepare a two-sized micro-perforated nanofiber membrane and explored its acoustic performance and mechanism as a small-size acoustic structure in the field of low-frequency noise reduction. The low-cost, non-toxic, and high-spinning speed polyvinyl butyral (PVB) was used as the raw material, which was developed into the nanofiber membrane by electrospinning. On this basis, PVB two-sized micro-perforated nanofiber membranes were fabricated through mechanical drilling. The effects of partition, perforation parameters, thickness, and cavity depth on acoustic performance were investigated theoretically and experimentally. The results demonstrated that the two-sized micro-perforated nanofiber membrane had excellent acoustic performance both in the low and medium frequencies. The addition of the partition not only broadened the sound absorption bandwidth but also shifted the resonance absorption peak to low frequency. Furthermore, by reasonably selecting and optimizing the structural parameters such as perforation parameters, fiber membrane thickness, and cavity depth, the range of effective sound-absorbing frequency bands could be adjusted to better meet the demand for noise reduction. Two-sized micro-perforated nanofiber membrane’s effective acoustic absorption bandwidth could reach 2,136 Hz in the 100–2,500 Hz range, which accounted for about 89% of the whole bandwidth. PVB two-sized micro-perforated nanofiber membrane with its superior sound absorption performance and thin fiber structure body become the ideal choice for flexible and lightweight acoustic materials in the field of acoustic noise reduction.

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Recent research has identified a key limitation in the petroleum sector commonly used pour point depressant (i.e., EVA-copolymer), which shows decreasing efficiency as the paraffin wax content increases. To address this issue, this study explored the enhancement of EVA-copolymers as pour point depressants for waxy crude oil through the gamma irradiation grafting of homopolymers with long alkyl chains onto EVA copolymers to produce (EVA-g-p(HDOAB) and EVA-g-p(HDAOCP)⁺Br⁻). FTIR and ¹H-NMR spectroscopy show that EVA-g-p(HDOAB) and EVA-g-p(HDAOCP)⁺Br⁻) were successfully prepared using gamma radiation. Various concentrations (100, 500, 1000, 2000, and 5000 ppm) of the grafted EVA-copolymers were introduced into the crude oil. The grafted copolymers showed a significant reduction in pour point from 24°C to -18°C and -15°C at a 2000 ppm concentration, outperforming pure EVA, which only reduced the pour point to -9°C. Additionally, both grafted copolymers demonstrated notable viscosity and shear stress reductions, particularly at temperatures close to the pour point. The enhanced low-temperature flow properties are attributed to the synergistic effect of the grafted EVA-copolymer acting as nucleating agents that modify crystallization patterns and inhibit crystal growth. This study underscores the potential of using gamma ionizing radiation to develop high-performance PPDs for crude oil.

Self-healing polyurethanes are garnering attention as a smart material, and has significant application potential in aerospace, biomedical, and electronics fields. In this paper, castor oil is selected as a soft segment in place of petroleum-based polyol to enhance the mechanical properties of polyurethane while improving the mobility of molecular chains. Meanwhile, a polyurethane with good self-healing properties was successfully prepared by selecting 2,2`-Diaminodiphenyl disulfide (DTDA) containing disulfide bonds as a chain extender. As the proportion of DTDA increases, the initial thermal decomposition temperature of polyurethane decreases by 21°C. Cutting and tensile tests confirmed the high mechanical properties and self-healing characteristics of the polyurethane network. And the self-healing efficiency of the polyurethane materials was improved by prolonging the healing time and increasing the healing temperature. As the content of disulfide bonds and hard segments increased, the tensile strength of polyurethane increases progressively, the elongation at break decreased, and the R(stress) and R(strain) of each specimen tended to increase and then decrease. The healing efficiency of the specimen with a disulfide bond content of 13.45% was optimal, with both R(stress) and R(strain) reaching more than 99%.

In recent years, chemotherapy has been used in cancer treatment commonly. However, the hydrophobic property and non-selective apoptosis still limit its application. Recently, drug delivery systems (DDS) such as polymer micelles, liposomes, and dendrimers have been widely developed to improve the efficiency of chemotherapy. In this work, the amphiphilic polymer was used to encapsulate the Doxorubicin (DOX) through the self-assembly process to form the polymer micelles, and the drug release of DOX was controlled by the temperature-sensitive monomer (triethylene glycol methyl ether methacrylate, TEGMA) and redox-responsive group (disulfide bond, S–S). On the other hand, the intracellular internalization was improved by the photosensitizer drug (protoporphyrin IX, PpIX) through the photochemical internalization (PCI) process. The lower critical solution temperature (LCST) of micelles in this work was 37.6 °C, and the in-vitro test showed that 96% of DOX was released under acid conditions with the high level of redox agent. Finally, the chemotherapy was confirmed by the cytotoxicity assays and confocal laser scanning microscope (CLSM).

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Water pollution from the textile industry poses severe environmental and public health challenges due to the presence of toxic and persistent synthetic dyes. Effective wastewater treatment is crucial to mitigate these impacts. This study addresses the issue by developing a sustainable and cost-effective semi-interpenetrating polymer network (IPN) xerogel composite incorporating eggshell, hydroxyapatite (HAp), and chitosan for efficient dye removal. Ultrasonic-activated eggshell powder (UAESP), HAp, or their combination was integrated with chitosan-containing poly(methacrylic acid) (PMAA)-based xerogels to enhance adsorption capacities. Characterization using FTIR, SEM, EDS, XRF, BET, and tensile strength testing confirmed significant structural, textural, and mechanical enhancements. Adsorption experiments demonstrated high efficiency in removing dyes such as methylene blue, Congo red, crystal violet, and methyl orange, with the chitosan/UAESP + HAp composite achieving the highest adsorption capacity (98.4 mg/g) for Congo red. Kinetic studies revealed that adsorption follows a pseudo-second-order model, with chemisorption as the dominant mechanism. Furthermore, intraparticle diffusion analysis indicated that the adsorption process involved multiple stages, including boundary layer diffusion followed by intraparticle diffusion. Simulated textile wastewater tests confirmed the practical applicability of the xerogels, maintaining high dye removal capacities over multiple cycles. In conclusion, this study offers a sustainable and versatile solution for wastewater treatment, contributing to cleaner water resources and environmental sustainability.

The synthesis of microfibrillated cellulose (MFC) from under-utilized Nipah (Nypa fruticans) fiber was employed by chemical and mechanical treatments. MFC was synthesized through a 10% NaOH pretreatment, subsequently hydrolyzed with 35% maleic acid at varying temperatures and durations, and completed with 30 min of sonication. In addition, MFC without 10% NaOH pretreatment was synthesized using increased maleic acid concentrations at reduced temperatures and shorter durations, followed by harsh mechanical processing with a supermass colloider (SMC). The zeta potential value indicated that both methods effectively produced microfibrillated cellulose in a stable suspension. Defibrillation of cellulose into microsizes, referred to as lignin-containing microfibrillated cellulose (L-MFC), can be accomplished via a weak acid hydrolysis process using maleic acid, followed by a more intensive mechanical process, such as a supermass colloider. This method has demonstrated the ability to produce a stable MFC suspension with a reduced MFC diameter from under-utilized fiber of Nipah’s fronds.

This study investigated the potential of pistachio nut shells (PNS) as a biochar filler in short Turkish hemp (STH) fibre natural fibre-based polymeric composites. PNS were made into biochar through pyrolysis and incorporated into a polyester resin matrix reinforced with STH fibres at varying concentrations (5–25 wt. %). The composites were fabricated using compression moulding and characterised for their mechanical, thermal, acoustic, and water absorption properties. The results showed that the incorporation of PNS biochar significantly enhanced its tensile strength of 47.36 MPa, flexural strength of 82.88 MPa, impact strength of 28.68 kJ/m², and Shore-D hardness of 82.49, with an optimal concentration of 15 wt. %. The thermal conductivity increased to 0.185 W/m·K, while the water absorption in seawater and distilled water was minimised to 3.8% and 5.7%, respectively. The sound absorption properties were also improved, with a maximum noise reduction coefficient (NRC) of 0.30. However, at high biochar concentrations (> 15 wt. %), it led to particle clustering and void formation, resulting in reduced mechanical and acoustic properties. Scanning electron microscopy (SEM) revealed that these biochar composites had minimal void formation and strong interfacial bonding between the biochar and hemp fibres for the optimal 15 wt. % compositions. This highlights the feasibility of using PNS biochar as a sustainable filler in natural fibre composites, offering a promising alternative to synthetic materials with enhanced properties and reduced environmental impact.

Graphene oxide (GO) was synthesized using a modified Hummer’s method, and the influence of GO on the curing behavior, mechanical performance, abrasion resistance, and swelling resistance of acrylonitrile butadiene rubber (NBR) nanocomposites was extensively analyzed. The curing results indicated increased torques (minimum, maximum, and delta torque) and cure rate index, while scorch time and optimum cure time were reduced. The mechanical properties of the nanocomposites improved with higher GO content. Notably, NBR containing 6 phr of GO exhibited increases of 132% in tensile strength, 58% in tear strength, 10% in abrasion resistance, and 63% in stress at 100% elongation compared to unfilled NBR. Moreover, the nanocomposites demonstrated significant enhancements in both abrasion and swelling resistance. These findings highlight the potential of GO to effectively enhance the overall properties of NBR rubber.

A sustainable copolymer derived from natural sources, poly(decamethylene terephthalamide/decamethylene isophthalamide) (PA10T/10I), was synthesized along with a series of PA10T/10I composites incorporating graphene oxide (GO) at concentrations ranging from 0.05 to 1 wt.% via an efficient in-situ polymerization method. The study investigated the impact of varying GO content on the performance of PA10T/10I/GO composites. Antistatic property tests demonstrated that even a small amount of GO significantly reduced the surface resistance of PA10T/10I, with notable improvements observed at just 1 wt.%, enhancing the antistatic properties of the PA10T/10I matrix. Additionally, Differential Scanning Calorimetry (DSC) analysis revealed that the crystallization properties of PA10T/10I were improved by the incorporation of GO, with minimal changes in the melting points of the PA10T/10I/GO composites. The melting temperatures remained in the range of 289.6 ~ 281.9 ℃as the GO content varied from 0.05 to 1 wt.%. Thermogravimetric Analysis (TGA) and Heat Deflection Temperature (HDT) results showed that the PA10T/10I/GO composites exhibited excellent thermal stability, with PA10T/10I/GO-5 (containing 1 wt.% GO) achieving a higher HDT of 105.9 ℃, surpassing that of the PA10T/10I matrix by approximately 10 ℃. Mechanical testing indicated that the tensile strength of PA10T/10I/GO-5 was approximately 28.20% higher than that of PA10T/10I, while the bending strength increased by about 23.03%. This study presents an efficient approach for fabricating polyamide composites with outstanding antistatic, crystallization, thermal resistance, and mechanical properties via in-situ polymerization, thereby facilitating the practical application of GO-based fillers.