Iranian Polymer Journal最新文献

Bleeding is one of the main causes of death in the world, accounting for about 30% of deaths. Blood clotting substances, especially natural substances, play an important role in reducing this mortality. In addition to shortening blood clotting time, these substances should have characteristics such as biocompatibility, biodegradability, and low cost. In this research, an optimal combination of oxidized cellulose, gelatin, and sodium alginate has been investigated as a hemostatic powder. Oxidized regenerated cellulose (ORC) was used in this study due to its coagulating properties and low toxicity. Additionally, zinc oxide has been used as an antibacterial agent in this composition. The oxidation degree of oxidized regenerated cellulose was calculated to be 22%. In this research, Design Expert software was used to determine the optimal composition and gelation time. The variables of this experiment were the sodium alginate/gelatin composite, oxidized regenerated cellulose, and zinc oxide. The results showed that by increasing the amount of sodium alginate, the gelation time decreased, and also by increasing zinc oxide, the number of bacterial colonies decreased. Studies show that increasing the amount of sodium alginate increases the properties of the gel. The results show that the combination of 75% sodium alginate, 23% gelatin, 1% ORC, and 1% ZnO has the best performance in creating a stable and effective gel for controlling deep and superficial wound bleeding.

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Flame-retardant polystyrene (PS) composites were fabricated via melt extrusion using recycled polystyrene particles (R-PS) as the matrix, intumescent flame retardant (IFR) as the primary flame retardant, and kaolin (Kaol) along with carbon microspheres (CMS) as synergistic additives. The flame retardancy, mechanical performance, and thermal behavior of the composites were systematically evaluated. Key findings: CMS and IFR exhibit synergistic flame-retardant effects in the R-PS. The R-PS/26IFR/4CMS composite demonstrates a limiting oxygen index (LOI) of 30.4% and achieves a UL94 V-0 rating (1.5 mm thickness). Moreover, CMS incorporation enhances both the mechanical properties and thermal decomposition temperature of the composite. Kaol synergistically interacts with IFR in R-PS, simultaneously improving the composite’s mechanical strength, thermal stability, and heat deflection temperature. Dual incorporation of Kaol and CMS into the R-PS/IFR composites yields superior comprehensive performance. The optimized R-PS/26IFR/2Kaol/2CMS composite attains an LOI of 31.8% with UL94 V-0 rating (1.5 mm thickness). Its tensile strength, flexural modulus, flexural strength, and notched impact strength reach 31.2, 2056.4, 45.2 MPa, and 6.5 kJ·m^− 2, respectively, representing enhancements of 16.4%, 2.3%, 5.6%, and 25.0% compared to the R-PS/30IFR. Both additives significantly improve the compactness and structural integrity of the char residue post-combustion.

Heavy metal ion pollutants cause notable environmental pollution, and threaten human life and ecological systems. In this study, an innovative hollow glass microspheres (HGM) composite adsorbent, PA-MHGM, was synthesized by grafting polyaspartic acid (PA) biomass onto the surface of HGM. The characterization findings demonstrated that the amino and carboxyl groups were effectively grafted by a silane coupling agent and PA biomass. The specific surface area significantly increased from 3.469 to 90.140 m²/g, with a mean pore size of 26.7808 nm. The capacity of PA-MHGM to adsorb Pb(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) was in the order of Pb(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Additionally, the adsorption mechanism under the experimental conditions was quantitatively characterized using a pseudo-second-order kinetic model and Langmuir isotherm. The optimal uptake capacities for Pb(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) are 160.18, 132.86, and 64.42 mg/g at 298 K. Thermodynamic characterization indicated that the adsorption process was spontaneous and exothermic. The sorption mechanisms indicated that chelation interactions played a key role in the adsorption process. Furthermore, the adsorbent showed no significant decrease after five cycles, and once saturated with pollutants, could be readily restored through solution desorption, demonstrating its adequate stability and regenerative capacity.

As sustainable material continues to gets its importance in the current scenario by emerging as a promising alternative eco-friendly material. The current research work focuses on enhancing the mechanical properties of hybridized kenaf (K), bamboo (B), poly (lactic acid) (PLA) green composite through Taguchi coupled grey rational analysis (GRA) statistical model for identifying the optimized fiber process parameter of different stacking sequence, concentrations of the sodium hydroxide (NaOH) (3%, 5% and 7% weight/volume) and the duration of the chemical treatment (1, 2 and 3 h). The ANOVA analysis was performed to confirm the statistical significance of all the parameters selected for the experimental study of mechanical traits in the developed samples. From GRA, the optimum set of conditions for producing superior mechanical characteristics was identified with a stacking sequence of K/B/B/K utilizing a chemical concentration of 5% for a treatment duration of 1 h. In addition, a hybrid nano-biocomposite was developed by incorporating various weight percentages of Halloysite nanotubes (HNT) with PLA matrix to the optimized conditions specified. This incorporation of HNT into the PLA matrix has led to a significant enhancement in mechanical properties, with better performance observed at 1.5 wt% HNT loading. Morphological characterizations also confirm the uniform dispersion of HNT throughout the PLA matrix, attributing to strong interfacial adhesion and interaction, thereby enhancing mechanical strength. The study provides a better understanding that fabricating hybrid green nanocomposites with proper process parameters and material combination may lead to better mechanical strength, which can be used for roofing applications in green building structures.

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A novel star-shaped auxetic metamaterial, inspired by the cross-sectional structure of octopus arms, is introduced in this study. The structure is fabricated using Digital Light Processing (DLP) 3D printing with a thermoset resin, combining high-resolution additive manufacturing with robust material properties. Using a combination of DLP fabrication, experimental compression testing, and finite element simulations, the mechanical behavior of the metamaterial was systematically investigated. To assess mechanical performance, parametric studies were conducted on different internal X angles and fillet radii, analyzing their influence on stiffness, energy absorption, stress profiles, and force-displacement characteristics. The deformed shapes, stress, and strain distributions observed experimentally and numerically were consistent, highlighting the unique mechanical response of the material. Stress and strain contours highlighted maximum stress localization at sharp edges between cells, aligning with areas experiencing the highest strain. Results reveal that decreasing the X angle enhances energy absorption by up to 65.7%, through the improvement of both stiffness and maximum force. Although the stiffness is only slightly affected, further increasing the fillet radius beyond 0.11 mm results in significant improvements in both maximum force by almost 15% and energy absorption by almost 22%. The proposed star-shaped design offers a practical strategy for spatially tailoring mechanical properties, making it highly suitable for applications such as chest protectors.

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The recovery of bismuth from aqueous media has garnered growing attention due to its dual relevance to environmental safety and industrial resource sustainability. This study systematically explores the adsorption kinetics and equilibrium isotherms governing the adsorption of Bi(III) using polymer inclusion membranes (PIMs), as polymeric adsorbent, fabricated from polyvinyl chloride/di-(2-ethylhexyl) phosphoric acid (PVC/D2EHPA) and poly(vinylidene fluoride-co-hexafluoropropylene)/D2EHPA (PVDF-HFP/D2EHPA). Batch adsorption experiments were performed under optimized conditions, and the resulting data were fitted to pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Among these, the pseudo-second-order model exhibited the best fit, indicating chemisorption as the primary mechanism. Additional support from Elovich and intraparticle diffusion models suggests a multistep adsorption pathway involving both surface interaction and internal diffusion. Adsorption equilibrium data were analyzed using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) models. The Langmuir model showed excellent agreement, suggesting monolayer adsorption onto homogeneous active sites, while D–R isotherm analysis further confirmed a chemisorptive interaction with mean adsorption energies ranging from 12.91 to 13.87 kJ mol^− 1. Maximum adsorption capacities were approximately 50 mg g^− 1 for PVC/D2EHPA and 40 mg g^− 1 for PVDF-HFP/D2EHPA membranes. These findings offer mechanistic insights into the adsorption behavior of Bi(III) on PIMs, contributing to the development of efficient, selective, and reusable membrane systems for heavy metal remediation from aqueous environments.

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This study presents a comprehensive exploration of advanced synthesis and functionalization strategies to significantly enhance the electrical and thermal properties of carbon nanotube (CNT) polymer composites. Leveraging techniques such as in-situ polymerization, electrospinning, and solution-based processing, the research achieves uniform CNT dispersion and robust interfacial bonding with the polymer matrix. These innovations result in remarkable property enhancements, including up to a 150% increase in electrical conductivity and a 200% improvement in thermal conductivity. Such advancements are pivotal for applications in industries that demand high-performance materials, including aerospace, automotive, energy storage, and electronics. For instance, CNT composites demonstrate superior heat dissipation in thermal management systems and enhanced electrical integrity in energy storage devices and flexible electronics. The study emphasizes the role of functionalization strategies, both covalent and non-covalent, in optimizing the compatibility of CNTs with diverse polymer matrices. These approaches significantly reduce the percolation threshold, allowing continuous conductive networks at lower CNT loadings while maintaining material flexibility. Rigorous characterization through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and laser flash analysis (LFA) validates these improvements, showcasing the potential for scalable application. Beyond these advancements, the research identifies key challenges, including scalability, cost-effectiveness, and sustainability. It proposes future directions to address these issues, such as green chemistry approaches and application-specific designs. This work underscores the transformative potential of CNT polymer composites, paving the way for innovative applications in critical engineering sectors and establishing a new standard for high-performance materials.

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Due to their high strength-to-weight ratio and ease of processing, epoxy resins are widely used in modern composite applications; however, their low wear resistance remains a limitation in demanding service environments. In this study, the improvement of mechanical and tribological performances of composites produced by reinforcing aluminum oxide (Al₂O₃) particles of different sizes into the epoxy matrix was investigated. The epoxy composites were modified with Al₂O₃ particles of 1% by weight in four different size ranges (1–2, 10, 44, and 180–250 μm), which were evenly distributed using ultrasonication. In the tensile test, sample with a particle size of 44 μm exhibited the highest value at 71.7 MPa. Tribological tests were performed in accordance with ASTM G99 standard. Tribological tests were conducted at loads of 5 and 10 N, sliding speeds of 1.75 and 2.25 ms⁻¹, and a fixed sliding distance of 1000 m under dry sliding conditions. The lowest wear loss was observed (0.869 × 10⁻⁹ m³) in the 44 μm sample under a load of 5 N and a speed of 2.25 ms⁻¹. The morphology of surface wear was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). In samples characterized by larger particle sizes, the wear marks had a smoother appearance. The application of a predictive modeling technique allowed the identification of the main factors influencing the wear rate, volumetric loss and coefficient of friction (COF).

This study presents a novel single-component, moisture-curable sealant formulation based on silyl-terminated polyether (MS) polymer, reinforced with synergistic nanofillers including fumed silica and nano-calcium carbonate. The primary objective was to enhance the mechanical performance, thermal stability, and rheological behavior of the MS-based system through the strategic use of nanotechnology. The optimized formulation exhibited a tensile strength of 1.73 MPa and elongation-at-break of 175%, while shear strength increased to 1.97 MPa after seven days of curing under controlled temperature and humidity. Fourier transform infrared spectroscopy (FTIR) confirmed stronger intermolecular interactions and improved crosslinking density due to the presence of reactive nanoparticles. Thermogravimetric analysis (TGA) showed a noticeable enhancement in thermal resistance, particularly with fumed silica loading up to 0.9 wt%, which delayed thermal decomposition. Additionally, nano-calcium carbonate at 31.7 wt% contributed to better dimensional stability and homogeneous filler dispersion within the polymer matrix. The inclusion of 0.6 wt% fumed silica resulted in a 155% increase in adhesive strength compared to the unfilled formulation. Rheological analysis revealed superior thixotropy and sag resistance, making the sealant suitable for precision applications such as vertical joints or overhead installations. Overall, this work underscores the potential of nanofiller-enhanced MS polymers to meet demanding performance criteria, offering a scalable and robust solution for industrial sealing applications.

Phase change materials are capable of undergoing phase transitions when the ambient temperature changes, presenting excellent energy storage properties. In this study, for the first time, we incorporate lignin into polyethylene glycol monomethyl ether, making the prepared phase change material less prone to liquid leakage and exhibiting excellent heat storage performance. The composite phase change material MPEG-g-EHL was prepared by grafting polyethylene glycol monomethyl ether (MPEG) onto lignin (EHL) skeleton carrier using the chemical grafting method with toluene-2,4-diisocyanate (TDI) as the cross-linking agent. The polarization microscopy (POM) patterns clearly reveal significant differences in crystal morphology between MPEG and MPEG-g-EHL. The grafting structure is confirmed by the results of FTIR and XRD analyses and the maximum grafting ratio is 85.73%. When the mass ratio of MPEG to EHL is 90:10, its enthalpy efficiency reaches its maximum value of 80.30%. At this point, its melting enthalpy value is 124.80 J g⁻¹, and its crystallization enthalpy value is 106.04 J g⁻¹. The composite phase change material MPEG-g-EHL is still thermally stable after 100 cycles of heat and cold, and it has a good latent heat energy storage property. These outstanding properties make it show broad application prospects in energy storage fields such as building energy conservation and temperature control, industrial waste heat recovery, and solar thermal storage systems.

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