Polymer Science, Series A最新文献

This report studied the effects of glass fiber (GF) on the mechanical properties of polyamide 6/acrylonitrile butadiene styrene (PA6/ABS) compounds with styrene-ethylene/butylene-styrene (SEBS) as a compatibilizer. Samples with various PA6/ABS/GF compound mixing ratios were prepared by injection molding with 0, 10, 15, 20, 25, and 30 wt % GF. The ratio of PA6/ABS was fixed at 50/50 and the compatibilizer SEBS was 5 wt %. The results showed that the tensile strength reached the maximum value of 83.44 MPa at 15 wt % GF when increasing the GF content. Moreover, the flexural strength increased to 104.90 MPa when the GF content increased from 0 to 30 wt % GF. SEM analysis revealed good adhesion between GF filler and PA6/ABS resin, indicating the good effect of SEBS compatibilizer. This research aims to develop a method of mixing materials to produce the desired mechanical properties. Potential applications can be recycling PA6 and ABS into insulation or fire-retardant materials by mixing with an appropriate amount of GF.

The thermodynamic functions (Gibbs free energy, enthalpy, and entropy of mixing) of TOPAS polycycloolefins (ethylene–norbornene copolymers) in chloroform at 298 K have been determined using microcalorimetry and isothermal equilibrium sorption of solvent vapor. TOPAS-5013 and TOPAS-8007 copolymers with norbornene contents of 46 and 35 mol%, respectively, have been studied. The concentration dependences of the thermodynamic dissolution functions have been examined for samples obtained by various methods: pressed commercial pellets and copolymer films cast from chloroform solutions. Thermodynamic modeling was used to calculate the Flory–Huggins enthalpy parameter and parameters characterizing the nonequilibrium state of the polymer glass. It has been shown that intermolecular interaction with chloroform is characterized by a Flory–Huggins enthalpy parameter of 0.25 ± 0.04 and is almost independent of the copolymer composition and the film fabrication method. At the same time, the proportion of metastable vacancies as a parameter of the glassy structure depends on both factors. The degree of nonequilibrium of the glassy state of TOPAS copolymers decreases with decreasing norbornene content in the copolymer chain and in the case of solvent-based film casting.

The effect of molecular weight characteristics of high-density polyethylenes in a wide molecular weight range from ultrahigh to low molecular (polyethylene, close to the brittleness threshold), as well a reactor polymer composite ultrahigh-molecular-weight PE–HDPE, which were synthesized in the presence of a heterogeneous catalyst based on VCl₃, on the structural parameters and deformation–strength properties of polyethylene was studied. It was shown that the supramolecular structure parameters and deformation–strength properties of the synthesized polyethylenes correlate with their molecular weight characteristics. Polymers with a MW lower than that of ultrahigh-molecular-weight PE and a reactor polymer blend ultrahigh-molecular-weight PE/HDPE are characterized by bimodal MWDs with a wide M_w/M_n. With decreasing MW, the proportion of a high-molecular-weight fraction decreases. As a result of structural changes, the lamellar long period L_p decreases due to the thinning of the intercrystalline amorphous gap L_a, which increases the plasticity of the material and decreases its strength.

The concentration dependences of the viscosity of magnetic fluids Fe–glycerol/water, Fe–ethylcellulose/DMAA, FeO_x–polyoxypropylene diol/water, FeO_x–ethylcellulose/DMAA, Fe₇Ni₃–ethylcellulose/DMAA, and Fe₇Ni₃–glycerol/water have been determined in a magnetic field and outside the field. Applying a magnetic field increases the viscosity of magnetic fluids by 2–4 times, and the concentration dependence of the magnetic-field effect on viscosity can be described by a curve with a maximum.

Continuous hollow fibers have been obtained for the first time from solutions of poly(2,5(6)-benzimidazole) in phosphoric acid. The rheological behavior of the solutions has been studied, and the kinetics of precipitation of the dope solution with water and 40% NaOH solution has been investigated. It has been shown that water is a soft precipitant, whereas the concentrated alkali leads to hard coagulation and the formation of vacuole defects. The operating parameters of the fiber spinning, such as the ratio between the volumetric flow rate of the internal precipitant to the flow rate of the polymer solution and the nature of the internal precipitant have a decisive influence on the morphology of the resulting fibers. As a result, a laboratory technology for spinning of hollow fibers of poly(2,5(6)-benzimidazole) with a monolithic and asymmetric structure has been elaborated, their thermal properties have been investigated, the residual solvent content in the fiber has been estimated, and the value of the limiting oxygen index has been determined. It has been shown that the hollow fibers of poly(2,5(6)-benzimidazole) have a great potential for use in high-temperature membrane separation.

Following pretreatment, aramid fiber (AF) powder was blended with polyether sulfone (PES) resin powder to fabricate a novel composite material compatible with selective laser sintering (SLS). Tensile and bending specimens of polyether sulfone/aramid fiber (PES/AF) composites were fabricated via selective laser sintering. This study examined the effects of aramid fiber content (0‒4 wt %) on microstructure, mechanical properties, density, and surface quality of SLS-fabricated parts. The reinforcement mechanism of AF in the PES matrix was also investigated. Experimental results demonstrate that incorporating appropriate AF content enhances the mechanical properties of PES sintered parts. Specifically, with increasing AF content, tensile strength, flexural strength, and density of PES/AF composites initially increased then decreased, while surface quality progressively deteriorated. At 1 wt % AF content, the tensile strength peaked at 10.59 MPa—an 11.17% increase over pure PES specimens. Flexural strength achieved its peak value (22.88 MPa) at 2 wt % AF, corresponding to a 41.06% enhancement versus pure PES.

The incorporation of fillers into polymer matrices is a well-established strategy to enhance mechanical, electrical, and thermal properties. However, filler–matrix compatibility remains a critical factor governing overall performance, often limiting the applicability of promising filler materials. While numerous studies have investigated individual filler systems, a systematic comparative analysis of multiple fillers within an identical polymer matrix remains notably absent. In this work, a comprehensive study is presented on the incorporation of three distinct fillers-clay, multiwalled carbon nanotubes (MWCNTs), and silver nanoparticles (AgNPs) into identical polyaniline-dinonylnaphthalene disulfonic acid (PANI–DNNDSA) gel matrices synthesized under controlled conditions to ensure uniform molecular weight and processing parameters. Each composite was evaluated for its structural, electrical, and mechanical properties to elucidate filler-specific influences and compatibility with the host matrix. The findings contribute valuable insights for both academic research and industrial applications, facilitating informed filler selection for advanced polymer design.

To investigate the effects of the different types and content of monomer units and molecular weights M_ns on the thermal, mechanical and barrier properties of the copolymers. Here, three unsaturated poly(L-lactic acid-co-butyrate itaconate) (P(LA-BI)), poly(L-lactic acid-co-butyrate fumaric) (P(LA-BF)), and poly(L-lactic acid-co-butyrate maleic) (P(LA-BM)) copolymers were synthesized by melt polycondensation and subjected to repeated grading. Based on a solvent/non-solvent (chloroform/n-heptane) mixture, an original sample was fractionated into 9–10 fractions. As the fractionation proceeded, the alterations in the monomer units content and M_ns of the three copolymers showed disperate trends. The P(LA-BI) with 10.4% PBI content reaches a maximum value of M_n 8.82 × 10⁴ and has the best physical properties. The elongation at break and oxygen transmission rate (OTR) were 491.3% and 106 cm³/m² d^–1 respectively, and the degree of crosslinking was 7.7%. P(LA-BF) exhibited the second-best M_n and physical properties, while P(LA-BM) displayed the worst physical properties. The elongation at break was 3.4% and the oxygen transmission rate (OTR) was 389 cm³/(m² d) at 7.3% BM.

Today, silicon solar modules (SM) represent the most efficient and environmentally friendly renewable energy source. However, as the market for these modules grows, problems with waste and environmental sustainability arise in parallel. Creating SM recycling technologies that fully circulate materials without waste and reuse components is a key issue that must be addressed within corporate social responsibility frameworks for environmental protection. An important step in resin recycling is separating the laminate from poly(ethylene-co-vinyl acetate) (EVA), which is commonly used as an adhesive in resin. Work has been done to reduce EVA using various organic solvents, with parameters such as type of solvent, residence time, and temperature taken into account. It was found that chlorinated hydrocarbons, such as trichloroethylene, chlorobenzene and chloroform, can effectively cause EVA swelling due to their polarity. Aromatic hydrocarbons like toluene and o-xylene provide sufficient interaction with EVA, which makes them more advantageous for industrial applications since they pose less danger than chlorine-containing solvents. Among the solvents tested, toluene turned out to be the best. The second series of tests were carried out using toluene alone, optimizing the separation process of EVA from SM components. The recovered EVA was then studied using various methods, including NMR, UV, Fourier spectroscopy, TGA, and DSC. These studies showed that reconstituted and reference EVAs exhibited similar properties without significant changes in composition. This indicates that reconstituted EVAs can be reused in SM or other applications.

This work focuses on the development of a biodegradable and biocompatible polymer composite based on poly(butylene succinate) (PBS) and nano-layered silicates Montmorillonite (MMT) with appropriate properties for the bone tissue engineering application. The MMT was previously modified with poly(ethylene glycol) (PEG) to increase its compatibility with the PBS and then the PBS/MMT-PEG composites were then prepared by melt mixing method. The mechanical results showed that MMT can improve the impact and flexural strength of PBS; only by adding 1% MMT the impact strength was increased by 6.8% with MMT and 13.3% with MMT-PEG, this material has relatively good mechanical properties and is suitable for bone splint applications. Moreover, the hydrophilicity of PBS composite scaffolds increased after adding MMT and increased even more with MMT-PEG. The density of composite materials is still much smaller than the materials currently used for implants. Samples were soaked in a simulated body fluid, the neoformation of bone-like apatite layer on their surfaces due to their bioactivity. The surface morphology of all samples was investigated using scanning electron microscopy (SEM) coupled with energy-dispersive X‑ray (EDX) spectroscopy. The result showed that PBS/MMT-PEG scaffolds were biocompatible and that they promoted mineralization more efficiently than pure PBS and PBS/MMT scaffolds. These results suggest that PBS/MMT-PEG scaffold has potential application in bone repair.