Journal of Polymer Research最新文献

Carbon template (graphene oxide (GO) and carbon fiber (CF)) based magnetic nanomaterials like G-t-F (GO-Fe₃O₄), G-t-FC (GO-CoFe₂O₄), and CF-t-F (CF-Fe₃O₄) were synthesized for this work and successfully incorporated into poly (lactic acid) (PLA) matrix. Saturation magnetism was observed in the ferromagnetic region for synthesized templated materials. PLA-based composites were fabricated by solution casting and filler loading varied in the range of 0.5–2 wt.%. An investigation was conducted on the effects of magnetic filler's nature and structure on the material identities, thermal behaviors, and melt flow properties of the composites. Thermal stability was improved for MC-G-t-F-0.5, and nucleation properties were observed through DSC analysis. Rheology investigations under a magnetic field (current: 0–0.6 A) indicated that the flow behavior of composites is similar to that of magnetorheological fluid. Han plot, Cole–Cole Plot, and Van-Gurp-Palmen plot were studied, and network formation was observed under a magnetic field. Constitutive mechanical models such as Bingham, Casson, and Herschel-Bulkley (HB) were utilized to determine magnetorheological (MR) flow parameters. In the case of a representative magnetic particle nanocomposite, PLA/G-t-F, the dependency of yield stress with G-t-F weight fraction (φ) and magnetic flux density (B) was investigated and recorded. It was observed that composite melt behavior is dependent on the type of magnetic filler, weight fraction, and magnetic flux density.

Effects of concentration (0–0.5 wt%) and type of thermally reduced graphene oxide (TRGO) and diblock copolymer-grafted TRGO, namely, TRGO-g-poly(butyl acrylate)-b-poly(methyl acrylate-co-glycidyl methacrylate) (TRGO-Gx-yK) with GMA compositions in P(MA-co-GMA) at 10 or 20 mol% (x = 10 or 20) and M_n for grafted polymer PBA-b-P(MA-co-GMA) at 30 K, 17 K, or 8 K (y = 30, 17, or 8), as low-profile additives (LPA) for unsaturated polyester resins (UP), on cured sample morphologies and properties of low-shrink UP after cure at 110 °C have been investigated. The decreasing order of compatibility for styrene (St)/UP/TRGO-polymer system before reaction, as predicted by the molecular polarity difference per unit volume between UP and grafted polymer of TRGO-polymer, showed that TRGO-Gx- 8 K > TRGO-Gx- 17 K > TRGO-Gx- 30 K, and TRGO-G20-yK > TRGO-G10-yK. The trend was in agreement with that of decreasing mutual miscibility of St/UP/TRGO-polymer system after cure at 110 °C, as observed from SEM and TEM micrographs. Adding 0.5 wt% of TRGO-polymer with M_n = 8000 for PBA-b-P(MA-co-GMA) and 20 mol% GMA in P(MA-co-GMA) as LPA can lead to a decrease of volume shrinkage by 64%, an increase of Young’s modulus by 12%, a slight decrease of tensile strength by 9%, a decrease of impact strength by 14%, an increase of thermal conductivity by 22%, and a decrease of surface resistivity by 99.9%, when compared with that of neat St/UP cured system. All properties depended on M_n and GMA composition for grafted polymer onto TRGO, and followed the decreasing order of TRGO-Gx- 8 K > TRGO-Gx- 17 K > TRGO-Gx- 30 K and TRGO-G20-yK > TRGO-G10-yK > TRGO.

The mechanical properties of components manufactured via fused filament fabrication (FFF) are generally lower than those of injection-molded parts due to the layer-by-layer deposition process and its reliance on interlayer diffusion. Fiber reinforcement offers a potential solution by improving strength, but its influence extends beyond mechanical performance. Despite extensive research, a significant gap remains in understanding interlayer diffusion, mechanical anisotropy, and the thermal and surface effects of fiber reinforcement in FFF composites. This study examines the effects of 10 wt% carbon fiber (CF) reinforcement in acrylonitrile butadiene styrene (ABS) on interlayer diffusion across varying layer thicknesses and its influence on mechanical properties. Increasing the layer thickness from 0.18 mm to 0.34 mm in pure ABS raises pore density from 3.35% to 11.20%, significantly reducing tensile strength. In contrast, ABS-CF composites exhibit a 41.98% average increase in tensile strength and reduced sensitivity to layer thickness variations. Anisotropy analysis, further incorporating raster angle and build orientation, shows a reduction in tensile strength and strain variation by 57.32% and 78.09%, respectively, indicating improved mechanical consistency. Furthermore, ABS-CF demonstrates enhanced thermal stability, with increased thermal expansion of deposited strands promoting interlayer diffusion. This not only improves mechanical performance but also results in distinct surface characteristics, where overall surface roughness remains comparable or lower, yet individual layer-level roughness rises by 57.30%. Additionally, surface hardness improves by 26.67%. However, these enhancements come with a transition from ductile to brittle failure, likely due to non-uniform fiber distribution and thermal mismatch between ABS and CF during fabrication.

This paper investigates the effect of incorporating waste biomass-derived biochar into epoxy hybrid composites reinforced with glass fiber (GF). Hand lay-up methods were used to fabricate interlaced composites, maintaining a constant 20% weight fraction of glass fiber while varying the filler content from 0 to 20% by weight. The biochar filler, obtained from almond shells, was uniformly dispersed within the epoxy resin using ultrasonication. The mechanical properties (MPs), water absorption (WA), and thermomechanical (TM) of the almond biochar hybrid polymer composites (PCs) were comprehensively examined. Experimental results indicate that composites containing higher proportions of biochar filler exhibit increased water absorption. Notably, the tensile strength (TS) and flexural strength (FS) of the 10% almond biochar particulate addition exhibit the highest values 324.66 MPa and 376.12 MPa, respectively. The ABC10 composite shows an increase of 21.36 MPa in TS and 13.17% in FS compared to the ABC0 composite. Scanning electron microscopy analysis elucidates the dispersion of particles within the composites and the tensile mode of failure. Dynamic properties reveal improved damping characteristics, with the addition of 10% filler leading to higher storage modulus (SM) and loss modulus (LM). The ABC10 interleaved composite exhibited a maximum SM of 8496.4 MPa, which is 24.9% higher than that of the ABC0 interleaved composite, indicating increased stiffness. This suggests that the ABC polymer composites increased stiffness contributed to the higher storage modulus. Overall, this study underscores the potential of utilizing biomass waste-derived almond shell biochar as a cost-effective reinforcement in polymer composites, demonstrating its efficacy in enhancing various material properties.

During the electrospinning process, the choice of solvent significantly influences the size, surface morphology, mechanical properties, and drug delivery efficiency of electrospun fibers. This study investigates the effects of 2,2,2-trifluoroethanol (TFE) and a binary system of dichloromethane (DCM) and N,N-dimethylformamide (DMF) on the characteristics of poly(ε-caprolactone) (PCL, Mn = 80,000 g/mol) fibers loaded with vitamin D3 (VD3) from In-Silico and experimental perspectives. Electrospun fibers produced using DCM:DMF (80:20) exhibited larger diameters (2.53 ± 0.60 μm), greater roughness (17.90 nm), and higher interconnectivity due to DCM´s high volatility. In contrast, fibers spun using TFE showed smaller diameters (1.53 ± 0.50 μm), lower roughness (15.70 nm), and reduced size dispersion, attributed to the solvent's low surface tension and higher dielectric constant. Spectroscopic analyses (UV–Vis and 1H-NMR) confirmed the encapsulation of VD3 within the PCL fibers, demonstrating successful drug integration into the polymer matrix. VD3 release profiles indicated that fibers produced with DCM/DMF provided a more controlled release, with minimal differences between high (log K = -0.48; K = 0.33) and low (log K = -0.66; K = 0.22) VD3 concentrations. In contrast, TFE fibers exhibited higher release rates at high VD3 concentrations (log K = -0.072; K = 0.93) than low concentrations (log K = -0.63; K = 0.24). This behavior is attributed to the excellent VD3 retention in the DCM/DMF system and a more sustained release, supported by theoretical calculations of the interaction energy between PCL and VD3, solvation effects, and thermodynamic properties. Both systems achieved complete release over a similar timeframe, demonstrating consistent and prolonged behavior. Mechanical characterization revealed that TFE-derived fibers were stiffer (elastic modulus: 112.70 MPa) due to improved chain alignment, whereas VD3 acted as a plasticizer, reducing stiffness in both solvent systems. These findings underscore the critical role of solvent selection in tailoring electrospun fibers for controlled drug delivery, highlighting the importance of balancing morphological, mechanical, and release properties to optimize therapeutic applications.

Poly(lactic acid) (PLA)-based composites incorporated with silicon dioxide (SiO₂) nanoparticles are widely used in medical, aviation, automotive and other fields due to their excellent mechanical, antibacterial and biocompatibility properties. However, current research has primarily focused on the influence of a single type of SiO₂ nanoparticle at varying concentrations, and there is limited research on how the size and shape of hydrophobic SiO₂ nanoparticles affect the properties of PLA matrix. Here, this study prepares PLA/SiO₂ nanoparticle composites using hydrophobically modified SiO₂ nanoparticles of different sizes and shapes and investigates the effect of nanoparticle size and shape on composites. Mechanical and thermodynamic tests results show that the addition of SiO₂ nanoparticles can significantly improve the mechanical properties and thermal stability of PLA composites, which can be explained by the contribution of nanoparticle dispersion, interfacial interaction and particle morphology. Scanning electron microscopy images of the tensile fracture surfaces further verify the effect of different forms of SiO₂ nanoparticles on PLA matrix, offering valuable guidance for the design and optimization of composites in practical applications.

Temperature-sensitive copolymer is an important functional material, and its directional application in different fields is a hotspot in recent years. This work introduced temperature-sensitive polymers into membrane materials for separation and enrichment of metal ions, and the process was designed as follows: Firstly, the temperature-sensitive copolymers of P (N, N-diethylacrylamide-co-acrylamide) (P(DEA-co-AM)) was successfully synthesized with different monomer feed ratios by radical polymerization at 70 °C. Secondly, series characterization methods were adopted to study the structure of samples, and following results were achieved. After integrating the characteristic peak areas of the ¹H NMR, reactive ratios of DEA and AM was obtained by Fineman-Ross method(F-R) and Kelen-Tudos method(K-T), respectively, and result also evidenced that as the feed molar ratio of DEA to AM was 8: 2, the average segment length ratio between AM and DEA in P (DEA-co-AM) were 1.073: 8.072, respectively. FT-IR and DSC characterization results shown that the synthesized polymer was copolymer and random copolymer, respectively, UV–visible spectrophotometer test result showed the copolymer exhibited a good thermosensitive. Finally, a smart imprinted membrane was prepared by this copolymer with PVDF and was used for selectively adsorbing ruthenium (III) from the complex environmental, and experiments results documented that the imprinted membrane displayed a good adsorption capacity, which provided a great development potential in separation and enrichment of ruthenium (III) fields.

Metal oxide nanoparticle-polymer hybrids are appealing solid materials that combine enhanced chemical and physical characteristics with elasticity, making them highly suitable for electrical device applications. This study focuses on the preparation and characterization of hybrid films composed of carboxymethyl cellulose (CMC) and polyethylene oxide (PEO) in a 70:30 weight ratio, incorporated with zinc oxide and copper oxide nanoparticles (ZCNP). The films were fabricated using a solution casting method, with the nanoparticles synthesized via the sol-gel technique. The temperature dependence of key electrical properties, including dielectric constant (ε'), dielectric modulus, relaxation behavior, AC conductivity, and activation energy, was systematically analyzed. At frequency (f) = 10 Hz, ε' of the CMC/PEO and CMC/PEO-ZCNP (2 wt%) samples was 56.34 and 7916.36 at 308 K respectively, while it reached 6222.65 and 152364 when the temperature changes to 333 K. Their relaxation time (τ) dropped from 59.5 and 0.40 µs to 1 and 0.18 µs in the same temperature range. At f = 10 Hz and T=308 K, electrical conductivity (σ') improved, with CMC/PEO showing log(σ') = -9.3605 (σ' = 4.36E-10 Ω·m⁻¹) and 2% ZCNP achieving log(σ') = -7.3142 (σ' = 4.85E-8 Ω·m⁻¹). The results demonstrated a significant enhancement in the dielectric constant of the hybrid films compared to the unmodified polymer blend, while maintaining a low dielectric loss. These enhancements are attributed to the incorporation of zinc oxide and copper oxide nanoparticles, which promote multiple polarization mechanisms and enhance charge carrier dynamics. The findings suggest that these hybrid films hold great potential for use in high-density energy storage devices and integrated thin-film capacitors, offering a scalable and efficient solution for next-generation electronic applications.

Polystyrene, when present as microplastics, is a significant pollutant with detrimental effects on human health. In light of this issue, our study introduces a method for the degradation of polystyrene through photocatalysis and its subsequent removal from drinking water via filtration. We investigated the photocatalytic degradation of 500 nm polystyrene (PS) using the highly efficient In₂O₃-rGO nanocomposite under visible light. FESEM analysis demonstrated that, after 12 h of visible light exposure, the size of the polystyrene beads decreased from 500 to 280 nm. This process resulted in a 56% degradation efficiency of polystyrene by the In₂O₃-rGO nanocomposite. Furthermore, the degraded polystyrene beads began to form networks, and with continued exposure to visible light, they merged into larger aggregates, as observed in FESEM images. Raman spectroscopy showed an increase in the peak at 1003.20 cm⁻¹ with extended visible light exposure, indicating a crucial step in the degradation process. Additionally, FTIR analysis confirmed the formation of carbonyl groups with increased light exposure, supporting the degradation of polystyrene. Our study presents a method and mechanism demonstrating how the In₂O₃-rGO nanocomposite not only reduces the size of polystyrene but also facilitates the formation of networks among degraded polystyrene beads, aiding in the filtration of smaller polystyrene particles.

In this work, free radical solution polymerization was used to prepare polymeric nanocomposite films by copolymerization of flexible butyl acrylate (BA) monomer and modified nano−silica with methyl acrylate (MMA) monomer. Our findings showed that the addition of BA monomer and nano−silica had limited effect on the transmittance of PMMA films, and the transmittance could achieve as high as 93%. Perfect overall properties of the as−prepared films (with a tensile strength of 36 MPa and an elongation at break of 42%) could be achieved when the monomer MMA:BA was set as 6:2 at a nano−silica content of 20 wt%. The PMMA−based nanocomposite films prepared in this work possessed excellent transparency, desired toughness and good hydrophobicity, which made them potentially promising for the applications as protective films for polarizing films.