Journal of Applied Polymer Science最新文献

The release of heavy metals, for example, lead, cobalt, and copper, from industrial activities harms both human health and the aquatic ecosystem. One promising material to solve this problem is a smart hydrogel that can promote adsorption in response to temperature. In this study, we present a promising smart hydrogel of poly(N,N-dimethylacrylamide-co-N-isopropylacrylamide) (P(DMA-co-NIPAM)) as an adsorbent for heavy metal ions in water that has a thermoresponsive behavior. The swelling ratio showed the thermoresponsive behavior, with a decreasing swelling ratio with increasing temperature. The highest swelling ratio was possessed by DMA:NIPAM of 35:65 (mol%) and 3% MBA. The presence of heavy metal ions reduced the phase transition temperature (T _c) of P(DMA-co-NIPAM) hydrogel from 40°C to 35°C. Moreover, the adsorption capacity increased not only with the increasing initial concentration of heavy metal solutions, but also with the decreasing temperature at the pH optimum of 4.5 for Cu(II) and 5.5 for Co(II) and Pb(II). The increase in adsorption capacity of at least 25% at low temperature reveals the smart behavior of P(DMA-co-NIPAM) hydrogel as the adsorbent. The adsorption capacity of P(DMA-co-NIPAM) hydrogel decreased in the following order: Co(II) > Cu(II) > Pb(II), with the Langmuir model being the most suitable adsorption isotherm model.

Following the emergence of the information age, electronic devices have assumed a pivotal role in both individual and societal frameworks. Nevertheless, the deployment of electronic equipment exacerbates electromagnetic (EM) contamination, while environmental complexities amplify the risk of damage in electronic devices. In this work, aramid nanofibers (ANF), MXene, and shear stiffening gel (SSG) were combined into a flexible sandwich structure using vacuum filtration, directional freeze-casting solidification, and polyurethane encapsulation. The primary EM wave attenuation mechanisms of the ANF/MXene/SSG/MXene/ANF (A/M/S/M/A) structure are microscopic multireflection and ohmic loss absorption, demonstrating an EMI SE of 64.85 dB in the X-band. Simultaneously, this A/M/S/M/A structure can attenuate up to 50% of the impact force, which has good buffering capacity. The Polydimethylsiloxane (PDMS)/MXene-GO-NiNCs (MGN) triboelectric nanogenerator (TENG) fabricated from the A/M/S/M/A structure in this work can generate voltage under external stimuli, thereby enabling the recycling of mechanical energy. This flexible functional composite demonstrates significant potential for applications in wearable technology, electronics, and EMI shielding.

Cesium tungsten bronze (Cs_xWO₃), renowned for its high visible-light transmittance and strong near-infrared absorption, can be integrated with fibers to produce high-performance photothermal materials. In this study, Cs_xWO₃ was blended with polyamide 6/66 (PA6/66), and PA6/66-Cs_xWO₃ fibers were produced via melt spinning. Woven fabrics constructed from these fibers exhibit excellent photothermal properties. Surprisingly, after washing or rubbing has a negligible impact on the Cs_xWO₃ content within the woven fabrics. Under 1000 W/m² xenon irradiation for 6 min, the maximum woven fabrics temperatures can reach up to 62.8°C, 70.1°C, and 71.1°C for pristine, washed, and rubbed samples, respectively. Notably, near-infrared absorption and photothermal conversion performance were significantly enhanced after washing and rubbing; this is, the observed temperature increase effect of more than 11% demonstrates that it improves photothermal efficiency after washing and rubbing. Clothing made from PA6/66-Cs_xWO₃ fibers exhibit superior photothermal performance compared with ordinary clothing. These findings highlight the potential of PA6/66-Cs_xWO₃ woven fabric, with their high photothermal conversion efficiency and robust durability, for applications in cold environments, such as winter thermal apparel.

To address the weak interfacial adhesion in carbon fiber (CF)/polyamide 6 (PA6) composites, this study investigates the effects of sizing type, fiber length, fiber content, and sizing amount on composite structure and properties. Composites were prepared via melt blending and injection molding, and characterized using FTIR, XPS, DSC, SEM, and mechanical testing. Results show that an acrylic-based sizing with C–N groups significantly improves interfacial adhesion, increasing tensile and notched impact strength by 43% and 66%, respectively, over unsized CF. With 5 mm fibers at 15 wt%, optimal crystallinity and mechanical performance were achieved: tensile strength of 104 MPa and impact strength of 34 J/m, representing increases of 89% and 215% over pure PA6. A 4.0% sizing amount provided uniform coating and superior wettability, yielding tensile and impact strengths of 112 MPa and 36.2 J/m, with respective improvements of 35% and 38% over unsized CF. This work demonstrates the role of interfacial regulation in enhancing composite performance and supports automotive lightweight applications.

Despite the growing deployment of photovoltaic systems in arid regions, the degradation behavior of polymeric backsheets under arid-cold climates remains insufficiently understood. This study investigates the long-term aging of poly (ethylene terephthalate) (PET) backsheets exposed outdoors in Yuli (located in Xinjiang, China), a representative arid-cold environment. A comprehensive suite of analytical methods including NMR, GPC, FTIR, 2D-COS, mechanical testing, and other techniques was employed to characterize the physicochemical and structural changes. Upon aging up to 450 days, PET backsheet film exhibited pronounced mechanical embrittlement, discoloration, significant surface crystallization, and enhanced oxygen barrier properties. These changes are primarily attributed to UV-driven chain scission and progressive methylene oxidation. The results from Yuli were further compared with those from Chengdu (a typical humid subtropical climate) and from standardized xenon-arc and damp-heat tests. The extent and characteristics of acid accumulation were found to vary with climate; xenon-arc exposure induced rapid acid generation accompanied by ester degradation, whereas damp-heat aging produced only minimal detectable acids. Chengdu samples show intermediate behavior with sustained acid development. These findings reveal the limitations of existing standard protocols and offer mechanistic insights that can inform the design of climate-adapted accelerated aging protocols for evaluating photovoltaic reliability.

This study investigated the effects of rubber polarity on carbon nanotubes (CNTs) dispersion, the evolution of the filler network structure in composite materials, and mechanical properties by using nitrile rubber (NBR) with varying acrylonitrile (ACN) content as the matrix and incorporating CNTs. As the ACN content increased (the mass percentages of acrylonitrile are 18%, 28%, and 34%, respectively), the polarity of NBR enhanced, improving the interfacial interaction with polar CNTs, and significantly enhancing the uniform dispersion of CNTs in the rubber matrix. The results indicate that as ACN increases, CNTs influence the filler network structure of NBR/SiO₂ composites. In a rubber matrix with 34% acrylonitrile content, CNTs agglomerate, impairing the interaction between nitrile rubber and SiO₂. Conversely, in a rubber matrix with 18% acrylonitrile content, CNTs hinder the formation of an optimal filler structure with SiO₂. Dynamic mechanical properties were tested using dynamic mechanical analysis (DMA), and Mooney-Rivlin curves were analyzed to investigate the interactions between fillers, between fillers and rubber, and between rubber and rubber. This study revealed the regulatory mechanism of CNTs on the performance of NBR/SiO₂ composites, providing a theoretical basis for the design and modification of high-performance polar rubber/nanocomposites in subsequent research.

This study aimed to evaluate the effects of graphene nanoplatelets (GNP) and zirconium oxide (ZrO₂) as fillers in polypropylene (PP) composites. Different concentrations of GNP (0.01, 0.10, and 0.50 wt.%) and ZrO₂ (0.50, 1.00, 2.50 wt.%) were evaluated. Composites were characterized by morphological analysis by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile and flexural tests. TGA showed that ZrO₂ improved the thermal stability of PP, increasing T_5% from 410.5°C (neat PP) to 452.0°C, and T_50% from 452.9°C to 479.1°C when modified with 2.5 wt.% of ZrO₂. GNP promoted an increase in crystallinity up to 10.6% compared to neat PP, while ZrO₂ increased by up to 16.2%. Mechanical tests showed that tensile and flexural strength did not have significant variations. DMTA results showed that the incorporation of nanoparticles increased stiffness by reducing molecular segmental mobility and enhanced the viscoelastic stability of PP across the entire temperature range. Through SEM/EDS microscopy, it was possible to observe the presence of Zr in the composites containing ZrO₂ and O in the composites reinforced with GNP.

In the present investigation, bi-metallic zeolitic imidazolate frameworks (BM-ZIF), consisting of 75% Co²⁺ and 25% Zn²⁺ ions, were synthesized at ambient temperature in an aqueous environment. The BET surface area, along with the CO₂, N₂, and CH₄ uptake capabilities of BM-ZIF, was systematically assessed. Membranes based on Pebax-1657 were prepared by incorporating BM-ZIF particles into the polymer matrix, with filler content ranging from 5 to 25 wt% relative to the polymer. The dispersion of the inorganic filler within the membrane matrix, as well as the structural characteristics, physicochemical interfaces, and filler-polymer interactions, were characterized utilizing FESEM, FTIR, XRD, and DSC techniques. FESEM analysis substantiated the uniform dispersion of the filler throughout the membrane matrix. DSC results showed that crystallinity decreased progressively as the filler loading increased. The synthesized MMMs demonstrated enhanced gas adsorption characteristics relative to the Pebax membrane. Performance of the MMMs was assessed using a custom-designed experimental setup designed to test both pure gases and binary gas mixtures. For an optimal filler loading of 20 wt% BM-ZIF, a remarkable 122% increase in CO₂ permeability, alongside 59% and 50% enhancements in CO₂/N₂ and CO₂/CH₄ selectivity, respectively, was achieved compared to the unmodified Pebax. In the case of a binary gas mixture, the membrane exhibited a CO₂ permeability of 39.51 Barrer and CO₂/CH₄ separation factor of approximately 18.8. These findings elucidate the capability of bi-metallic ZIF fillers to augment the gas separation properties of MMMs, thereby presenting substantial advancements for applications in energy and environmental sectors.

This study investigates the novel microwave-assisted synthesis of a Chitosan-based Alkali Activated Fly Ash (CS@AAFA) composite beads to remove Malachite Green (MG). The synthesized materials were evaluated using FTIR for identifying the presence of functional groups, XRD for elemental composition and crystallinity, FEG-SEM for micro & nano surface structures and point zero charge. The MG dye removal experiments were conducted with a 617 nm wavelength by UV–Vis spectrophotometer. Adsorption parameters such as initial concentration (50–150 mg L⁻¹), contact time (0–150 min), dose (0.5–4 g L⁻¹), and pH (2–12) were investigated. The most favorable (91.8%) removal was observed at 27°C, 10 pH and 50 mg L⁻¹ MG concentration at a 2 g L⁻¹ dose of adsorbent. The isotherm, kinetic and statistical physics models indicate Langmuir type physiosorption with multilayer adsorption capacity of 65.1 mg g⁻¹. The field potential of the adsorbents was investigated through ionic strength and dye mixtures, ensuring the best adsorption onto the CS@AAFA composite surface. The adsorption mechanism suggests electrostatic interaction, hydrogen bonding, π–π stacking, n–π stacking and pore filling. The present investigation provides rapid synthesis and removal of MG dye using synthesized low-cost adsorbent with potential applicability in wastewater treatment.

Polymer composite bipolar plates (BPs) containing conductive carbon fillers are explored in this paper to develop BPs for proton exchange membrane fuel cells (PEMFC). Although various carbon-based fillers have been investigated, studies on hybrid systems combining carbon nanofibers (CNF) and multi-walled carbon nanotubes (MWCNT) with epoxy and other conductive fillers remain limited. To address this gap, this work examines the effects of incorporating a synergistic blend of CNF and MWCNT along with natural flake graphite (NG) and carbon black (CB) in an epoxy matrix to fabricate nanocomposite BPs via compression molding. The composite BP with 40:46:10:4 vol.% of epoxy, NG, CB, and CNF + MWCNT blend, respectively, achieves an in-plane electrical conductivity of 205 S cm⁻¹, flexural strength of 48 MPa, corrosion current density of 0.228 μA c m⁻², and thermal conductivity of 5.35 W m⁻¹ K⁻¹. The composite BP with 1.0 vol.% reduced Graphene Oxide (rGO) by expense of NG attains an increased in-plane electrical conductivity of 215 S cm⁻¹, flexural strength of 46 MPa, corrosion current density of 0.202 μA c m⁻², and thermal conductivity of 4.38 W m⁻¹ K⁻¹. The results confirm that simultaneous CNF–MWCNT incorporation is an effective approach for developing a hybrid nanocomposite BP material for PEMFC.