Iranian Polymer Journal最新文献

In recent years, the massive discharge and irrational accumulation of slag have led to the waste of land resources and serious environmental pollution problems. In this work, to explore the potential applications of slag, it was modified with silane coupling agent 3-aminopropyltriethoxysilane (KH-550) to improve its compatibility with polymer matrix. A series of low density polyethylene (LDPE)/modified slag (MS) composites were prepared using melt blending method. The results showed that the introduction of MS significantly improved the thermal and mechanical properties of LDPE in comparison to those of its pure form. The tensile strength, tensile modulus, and T_d5% of the LDPE/MS composites with 40 wt% MS content were enhanced by 58%, 113%, and 19.9 ℃, respectively. Furthermore, dynamic rheological analysis revealed that a higher MS filler content resulted in a higher restriction on the movement of the LDPE molecular chains. The application of slag in LDPE provides a feasible method of recycling slag and promoting sustainable development.

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The efficacy of a 3% ASA copolymer is examined in augmenting the mechanical properties of natural fiber composites. The batching process, which includes softening, lubricating, and conditioning, is applied in fibers, such as woven jute and non-woven manila hemp. This process is employed in the development of woven jute/epoxy, non-woven manila hemp/epoxy, and combined woven jute/non-woven manila hemp/epoxy composites to investigate their impact on their mechanical characteristics. Through various characterization methods, it was found that significant enhancements were observed in hybrid composites, particularly in the woven jute/non-woven manila hemp/epoxy composite. These enhancements include a maximum tensile strength of 52 MPa, a tensile modulus of 1.67 GPa, an impact strength of 9.6 kJ/m², and a flexural strength of 90 MPa. The observed improvements are attributed to the influence of a hard chain copolymer, with a glass transition temperature of 25.05 °C determined from differential scanning calorimetry (DSC) curves. Fiber surface treatment using a semi-continuous seeded emulsion polymerization method significantly impacts properties, enhancing fiber–matrix adhesion and mechanical performance, resulting in a 14% increase in both tensile and flexural modulus compared to untreated composites. Analytical techniques such as emulsion particle-size measurements using dynamic light scattering (DLS) and SEM further support these findings.

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A novel biocomposite material has been developed by reinforcing indigenous natural fragrant screwpine (FSP) fiber with polyester resin. Different sets of biocomposite materials are prepared using untreated and chemically treated (3%, 5%, 7% and 9% by weight of NaOH and sodium lauryl sulfate) FSP fibers for different concentration, time (1 h and 3 h) and fiber lengths (3 mm and 9 mm). The tensile, flexural and impact strength of the developed composites samples were studied and optimized through Design of Experiments (DOE). The NaOH (3% for 3 h) treated 9 mm fiber length FSP fibers reinforced polymer composite (FSPFRPC) shows a better tensile (53.17 MPa), flexural (65.84) and impact (21 J/m) strength than the untreated and other chemically treated FSP polymer composites. The strong bonding of the modified augmentation material with the matrix was analyzed from the sample images obtained from scanning electron microscopy. The DOE has been also employed to provide mathematical equation for optimization purpose. The heat resilience of the FSPFRPC samples was interrogated through thermogravimetric—derivative thermogravimetric analysis (TGA-DTG) to appreciate its performance under higher ambient temperature conditions which is revealed as 192 °C. The pin-on-disk experimentation helped to understand the wear behavior of the composite samples with minimum mass loss of 0.125 g. The water-absorption analysis performed on the composite samples revealed its behavior under humid conditions.

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Schiff bases (S1 and S2) were synthesized from the condensation reaction of 2-amino-6-ethoxybenzothiazole with 3-hydroxy-4-methoxybenzaldehyde and 3-hydroxy-4-ethoxybenzaldehyde. P-S1-A and P-S2-A poly(phenoxy-imine)s, and P-S1-O and P-S2-O poly(phenoxy-imine)s were synthesized through oxidative polycondensation (P) of S1 and S2 by NaOCl oxidant in alkaline (A) solution (10% KOH aquation solution) and by H₂O₂ (35% aquation solution) in THF organic (O) medium, respectively. The structures of the Schiff bases and poly(phenoxy-imine)s were characterized by FTIR, NMR, UV–Vis and TG/DTA investigations. The limit oxygen index (LOI) and heat-resistance index temperature (T_HRI) values were determined from thermogravimetric analysis data of compounds. The LOI values of poly(phenoxy-imine)s were between 21.16 and 33.87. The molecular weight distributions and glass transition temperatures of poly(phenoxy-imine)s were determined from gel permeation chromatography (GPC) and DSC, respectively. The M_n values of P-S1-O, P-S1-A, P-S2-O and P-S2-A were found to be 5800, 15500, 5600 and 9400 Da, respectively. Moreover, the polymerization degree (DP) values of P-S1-O, P-S1-A, P-S2-O and P-S2-A were calculated to be 18, 16, 47 and 28, respectively. The glass transition temperature (T_g) of P-S1-O, P-S1-A, S2, P-S2-O and P-S2-A were calculated from DSC curves at 115, 111, 102 and 128 °C, respectively. The surface images of poly(phenoxy-imine)s were determined with SEM analysis. The optical bandgap values of Schiff bases and poly(phenoxy-imine)s were calculated from UV–Vis measurements. The optical bandgap value of P-S2-A was calculated to be 1.95 eV.

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Amidst the relentless innovation in materials science and bone tissue engineering, the quest for next-generation bone graft materials with bespoke functionalities has emerged as a pivotal research domain. This study produced and characterized a novel bone healing material. First, we explained how three-armed polylactic acid (3s-PLA) was created in supercritical carbon dioxide (ScCO₂) and utilized as a matrix material. Following that, we described how the solution blending approach was employed to create three-armed polylactic acid/chitosan/nanohydroxyapatite (3s-PLA/CS/nHA) composites. The composites were then drug-loaded with prednisone acetate as a model drug utilizing the supercritical impregnation technique. Ultimately, the Ritger-Peppas model was substantially followed by the drug release of the drug-loaded composites when the in vitro drug-release kinetics of the drug-loaded materials were investigated. The porous structure of 3s-PLA was demonstrated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) hydrogen spectroscopy. Morphologic studies using scanning electron microscopy (SEM) revealed the homogeneous distribution of drug in the matrix of the mixtures as well as the porous structure of 3s-PLA and 3s-PLA/CS/nHA. The hydrophilicity of 3s-PLA/CS/nHA was examined by the use of water contact angle (WCA), revealing that the material in question has a hydrophilic water contact angle of 45.69°. Furthermore, research was conducted using one-way tests and investigations to characterize in vitro drug-release carrier materials under various drug conditions and temperatures. The carrier material consistently released up to 84.8% of prednisone acetate over the course of 72 h, demonstrating good control over prolonged release, according to the results.

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Nowadays, due to the rapid development of electromagnetic devices, it is necessary to prepare materials absorbing electromagnetic waves to reduce the harmful effects of these radiations on the environment and human health. Another application of these coatings is in the military, defense and aerospace industries. In this work, new microwave absorbing coatings with good adhesion were prepared by in situ polymerization of polyurethane in the presence of synthesized polyaniline and/or poly(aniline-co-melamine). The prepared materials were characterized by FTIR, XRD, TGA, DSC and SEM analyses. SEM images showed that the formation of nanotube particles in the copolymer was obtained in a molar ratio of 1 to 4 of melamine to aniline in a copolymerization feed. Polyurethane/poly(aniline-co-melamine) nanocomposite showed a better performance in microwave absorption ability than polyaniline/polyurethane, and the highest reflection loss in AM41 sample was −12.28 and −10.78 dB that appeared in the frequencies of 11.42 and 10.52 GHz, respectively. The electrochemical behavior of polyurethane/poly(aniline-co-melamine) nanocomposite was investigated using cyclic voltammetry and electrochemical impedance spectroscopy, and the results showed similar capacitive behavior for AM41 and AM10 nanocomposites, which proved that the change in morphology of AM41 caused better performance in absorbing microwaves.

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In a novel approach, the effect of twin-roll mixer temperature as well as fiber-matrix interaction on the ablation behavior and carbonized char structure was studied. Different ablative insulators based on ethylene propylene diene monomer (EPDM) were fabricated using a laboratory twin-roll mixer at cold (25 °C) and hot (60 °C) temperatures. Moreover, the effects of hydroxyl-terminated polybutadiene (HTPB), bis(3-triethoxysilylpropyl)tetra sulphane (SI-69) and polyethylene glycol 400 (PEG-400) as coupling agents at 2 and 3 phr levels were assessed. Curing rheometery, physical and mechanical testing, micro and macro-morphology images of insulator and char, thermal assesment and oxyacetylene torch test (T_flame = 3000 °C) were expolited. FE-SEM analysis of charred layers showed that PEG (2) EPDM-Hot, SI-69 (2) EPDM-Hot, and HTPB (3) EPDM-Cold samples (Table 1) formed a loose carbonized layer, which cannot resist under the oxyacetylene flame, resulting in low ablative resistance. The micro-morphology of hot processed samples displayed more compatible interplanar layers. The HTPB Hot (3)-EPDM sample (Table 1) showed a higher T_g (− 49.63 °C), cross-linked density (6.83 10^–4 mol/cm³), tensile strength (5.11 MPa), thermal stability (T_max = 476.60 °C), char layer compression strength (about 600 N at 1.75 mm displacement) and better dispersion of filler in the matrix than the other samples. Remarkably, the use of a hot twin-roll mixer and an appropriate coupling agent simultaneously suggests a synergistic effect in increasing the ablation resistance (the lowest ablation rates of 0.07916 mm/s and 0.3758 g/s) in HTPB Hot (3)-EPDM sample through better distribution and interaction of the fillers with the rubber matrix.

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The environmental crisis caused by the use of petroleum-based fibers and the massive depletion of petroleum resources threaten the sustainable development of mankind. Therefore, regenerated protein fibers have gained widespread attention for their green credentials, ingenuity and excellent compatibility. In this work, polyvinyl alcohol (PVA)/soy protein (SP)-carboxylated graphene oxide (GO–COOH) (PVA/SP–GO–COOH) composite fibers were prepared by wet spinning of aqueous solution containing PVA, SP, and GO-COOH. The composite fibers were analyzed for their morphology, structure, thermal stability, and mechanical properties. The results indicated that the composite fibers have both the glossy properties of SP and excellent mechanical properties of PVA. This was attributed to the good dispersion and compatibility of SP and GO–COOH in the PVA matrix. When GO–COOH was added at 0.5% (by weight), the tensile strength of the composite fibers reached 3.29 cN/dtex and the Young’s modulus was 113.92 cN/dtex, which increased by 87% and 67%, respectively, as compared to that of the pure PVA fiber. The moisture regains of the composite fibers reached 8.27%. Furthermore, the maximum decomposition temperature reached 326.7 °C and the thermal stability of the composite fibers increased due to the shielding effect of GO–COOH and formation of hydrogen bonding with the polymer.

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The present study aims to explore the cytotoxicity, physicomechanical, thermal, and barrier properties of Juglans regia leaf fiber (J) reinforced PHB-based films, with a focus on evaluating their suitability for biomedical applications. In this work, scaffolds are developed by incorporating varying concentrations (0.5%, 1%, 1.5%, 2% and 2.5%) of J into poly(hydroxybutyrate)/poly(vinylacetate) matrix by solvent casting. These are characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The results indicated that the sample containing 1.0% (by weight) J (PJ1.0) results in maximum values of the tensile strength (25 MPa) and storage modulus (1.61 GPa) at – 20 °C. Moreover, this sample exhibited favorable thermal, water barrier, and wettability properties. The hydrolytic degradation behavior of the composites is also studied at pH 7.4 and 37 °C for 16 weeks. It is observed that PJ1.0 degrades by 45%, whereas PHB experiences 18% degradation. Furthermore, the cytotoxic nature of the scaffolds is also assessed using C2C12 mouse skeletal muscle cell lines. The results confirmed that PJ1.0 does not show any cytotoxic effects when compared to pure PHB. Thus, findings of this study suggested the potential of Juglans regia fiber for the development of sustainable and mechanically robust materials for biomedical applications.

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In this work, to improve the antifouling and separation performance of polycarbonate (PC) membranes in the petroleum refinery wastewater treatment, various amounts of magnesium–aluminum (Mg–Al)-layered double hydroxide (LDH) nanoparticles (0–2 wt%) were incorporated into PC membrane, for the first time. The Fourier transform infrared (FTIR), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) characterizations confirmed the synthesis of Mg–Al LDH structure through the hydrothermal method, with different counter anions including nitrate (NO₃⁻) and carbonate (CO₃²⁻) presented in the interlayer spaces. The characteristics of the fabricated membranes were investigated using water contact angle and porosity analyses, FESEM and atomic force microscopy (AFM) techniques and mechanical properties. All membranes modified with Mg–Al LDH hydrophilic nanoparticles showed a lower water contact angle and higher porosity as compared to the neat PC membrane. The FESEM micrographs of the cross section of the membrane indicated that the inclusion of CO₃.Mg–Al LDH nanoparticles in the PC matrix led to the removal of the sponge-like layer of the membrane. The results of the petroleum refinery wastewater filtration experiment revealed that the irreversible fouling ratio (IFR) value decreased from 66.7% for the neat PC membrane to 10.5% and 19.1% for PC/CO₃ Mg–Al LDH-1.5 and PC/NO₃ Mg–Al LDH-1.5 nanocomposite membranes, respectively. The membrane separation performance, measured by the total organic carbon (TOC) indicated that filtrates from all nanocomposite membranes had lower TOC values compared to the neat PC membrane.

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