Advances in Polymer Technology最新文献

Synthetic dyes are extensively used in industries such as cosmetics, plastics, and textiles, but their release into water bodies poses a serious environmental and health hazard. Conventional wastewater treatment often struggles to remove these highly stable pollutants. Among the emerging solutions, adsorption using advanced polymer-nanomaterial hybrids has attained significant attention for its simplicity, efficiency, and eco-friendliness. This review emphasizes recent developments in polyvinylpyrrolidone (PVP)-based nanocomposites and hydrogels incorporating nanomaterials like Fe₃O₄, ZnO, NiO, MgO, CuO, CoFe₂O₄, reduced graphene oxide, graphene oxide, and carbon nanotubes (CNTs), for the removal of both cationic and anionic dyes from aqueous systems. We outline key synthesis strategies, structural features, and surface modification techniques that enhance adsorption capacity, reusability, and selectivity. Adsorption mechanisms are discussed in terms of isotherm and kinetic models, providing insights into structure-performance relationships. Special emphasis is placed on sustainability, including regeneration efficiency, and potential scalability for industrial wastewater treatments. By integrating material innovation with environmental application, this review underscores the potential of PVP-based nanomaterials as high-performance, reusable adsorbents for achieving cleaner water resources.

Injection moulding (IM) is a precise manufacturing process capable of producing tight-tolerance, functional plastic components with high-quality surface finishes. However, the growing use of stereolithography (SLA) 3D printing for rapid, low-cost mould fabrication presents a challenge, as the layer-by-layer process produces a stair-step geometry that promotes a keying effect, leading to reduced surface quality, premature tool wear and poor part release during moulding. The study addresses the problem by examining the influence of print orientation on the stair-step effect on SLA-printed tooling by assessing how post-processing (bead blasting, polishing) and CAD-applied textures can improve surface integrity and tool longevity. A short production trial using polypropylene (PP) coupons measured surface roughness, contact angle and tool degradation. Post-processed and CAD-textured moulds effectively masked the stair-step effect and improved lifespan, achieving Ra values consistent with IM standards (0.2–2.5 µm). In contrast, untreated moulds exhibited progressive wear and chipping before 20 cycles. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy confirmed mould material transfer causing surface contamination, while CT scans revealed warpage and dimensional variation of up to 13% due to print orientation. These findings demonstrate that targeted surface modification strategies significantly enhance the performance of SLA-printed moulds, providing a viable solution for short-run IM applications.

The performance of gap-filling materials, a key part of valve hall sealing, directly impacted the system’s overall firestopping effect. In this study, nanofillers were used to modify the gap-filling materials. The effects of nanofiller modification on the performance of the gap-filling materials were investigated through thermogravimetric analysis (TGA), oxygen index (OI) test, vertical burning test, cone calorimetry, muffle furnace calcination, and tensile strength test. The TGA results showed that using carbon nanotubes (CNTs) as nanofillers increased the initial decomposition temperature of the gap-filling material to 463.7 °C, with a residual char yield of 77.2% at 800 °C, significantly enhancing its thermal stability. Muffle furnace calcination images demonstrated that the nanofillers effectively improved the ceramic-forming properties of the gap-filling material. The OI increased to 37.1%, and the material achieved a V-0 rating in the vertical burning test. The peak heat release rate (pHRR) and total heat release (THR) were reduced to 65.1 kW/m² and 38.2 MJ/m², respectively, representing decreases of 57.8% and 49.2% compared to the unmodified gap-filling material. Additionally, the fire growth index (FGI) decreased, while the fire performance index (FPI) improved. These results indicated that nanofillers can significantly enhance the flame retardancy and intrinsic safety of gap-filling materials, thereby ensuring the safe operation of ultrahigh voltage (UHV) transmission lines and supporting the global advancement of UHV technology.

The relationship between structure and properties in polymeric materials explores how variations in polymer blend composition affect their microstructure and alter rheological, thermal and mechanical characteristics. This study focuses on polylactide (PLA)/poly(ε-caprolactone) (PCL) blend, which is selected for its biodegradable and biocompatible properties, enabling applications ranging from packaging to biomedical fields. PLA/PCL blends with different PCL loadings were processed in a twin-screw extruder. We assessed the correlation between blend microstructure and properties to analyse mechanical performance under various loading conditions. The blend with 10 wt% PCL exhibited droplet-matrix morphology with well-dispersed PCL particles, strong interfacial adhesion and notable crystallinity, as shown through scanning electron microscopy (SEM), rheological analysis, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The high PLA content, excellent dispersion and significant crystallinity resulted in elevated tensile strength and toughness, as well as reduced brittleness in tests. However, the material exhibited low notched Charpy impact strength. This indicates that it can deform under tensile and repetitive loads, yet exhibits poor resilience to sudden impacts under notched conditions. The droplet-matrix morphology is validated as the experimental tensile modulus aligns with Takayanagi model predictions. These findings emphasise the importance of blend microstructure in property development and how service conditions affect polymeric product performance.

The increasing demand for sustainable packaging alternatives has driven research into substitutes for petroleum-based plastics. This study develops eco-friendly composite films by incorporating tetrabutylammonium fluoride and dimethyl sulfoxide extracted jute cellulose nanocrystals (JCNCs) into polyvinyl alcohol (PVA) via the solution casting method. The properties of the prepared PVAJCNC composite films are compared to those of neat PVA and commercial nanocellulose (CoNC)-reinforced PVA composites to evaluate their performance. Morphological analyses reveal that all composite films of up to 1 wt.% loading exhibit uniform surfaces. Fourier transform infrared and X-ray diffraction analyses confirm the existence of strong molecular interactions between PVA and JCNCs. Thermal analyses show that the PVAJCNC 1% composite film exhibits a melting temperature of 191°C, an initial degradation temperature of 292°C, and reaches 50% weight loss at 388°C. Optically, PVAJCNC 1% composite film maintains over 79% transparency in the visible light region at 400–800 nm, while blocking over 40% UV-radiation at 200–400 nm. Mechanical testing demonstrates that incorporating JCNC significantly improves tensile strength (TS). The PVAJCNC 1% film exhibits a TS of 102.93 MPa and a Young’s modulus of 3254.18 MPa, representing a 70.85% and 56.41% improvement over the neat PVA film, respectively. Up to 3 wt.% loading, PVAJCNC composite films exhibit a moderate elongation at break of 6%–7%, which is desirable for balancing the flexibility and structural stability of packaging materials. Dynamic mechanical analysis also reveals higher stiffness values than the neat PVA film. The PVAJCNC 1% film exhibits a moisture uptake of 7.93%, resulting in 35.63% lower compared to the neat PVA film. PVAJCNC films exhibit comparable mechanical, thermal, and optical properties, and better UV and moisture barrier properties than PVACoNC composite films. These findings highlight the PVAJCNC composite as a promising, eco-friendly candidate for sustainable packaging applications.

Highland bamboo is a renewable and sustainable lignocellulosic material abundant in cellulose, making it ideal for a range of industrial applications. This findings aimed to extract cellulose (C) from Ethiopian highland bamboo and combined it with polyvinyl alcohol (PVA) to create biocomposites by means of the solution casting method. Several key properties of the biocomposite samples were analyzed, including water absorption, thermal performance, chemical composition, morphology, biodegradability, and mechanical strength. Biocomposites were produced with various PVA–cellulose (PVA–C) ratios (100/0, 98/2, 96/4, 94/6, and 92/8 wt.%). It was noted that water absorption decreased from 58.9% in pure PVA to 21.59% in the 92/8 PVA/C composite. Thermogravimetric analysis (TGA) revealed that PVA-reinforced with 6 wt.% C experienced an 80% weight loss between 290 and 380°C. Mechanical testing indicated an increase in tensile strength from 32.18 MPa in pure PVA to 37.60 MPa in the 94/6 PVA/C composite, followed by a reduction to 30.86 MPa. Moreover, the elongation at break fell from 288.72% in pure PVA to 127.25% in the 94/6 PVA/C composite before rising again to 216.75%. Additionally, SEM data show that the generated biocomposite has a strong network structure, suggesting that the cellulose and PVA matrix have strong interfacial contacts. Overall, the findings indicate that the addition of cellulose can improve the mechanical properties, thermal stability, biodegaradability, and water resistance of PVA-based biocomposites.

This study aimed to investigate the effect of the silane-to-silica ratio on the dissipative properties of carbon black (CB)/silica-reinforced SSBR compounds under dynamic loads used as the tread of tires. Six compounds were prepared with a constant total filler volume fraction but different silane-to-silica and CB/silica ratios. The research was carried out in two steps. First, the viscoelastic properties of the cured compounds were studied using the rubber process analyzer (RPA) and the dynamic mechanical thermal analysis (DMTA). Meanwhile, the data obtained from the tensile and volumetric change tests were fitted into a nonlinear hyper-viscoelastic model, and the material parameters were determined. In the second step, finite element analyses were performed using these parameters for two samples under tensile and shear loads. The variations of the loss factor with strain amplitude and temperature, as well as the computed dissipated energy, showed that increasing the silane content in silica compounds enhances the dissipation properties at both low and high temperatures, corresponding to traction and rolling resistance, respectively. This is due to the increased strength of chemical bonds between the filler and polymer chains. However, the finding of both methods reveals that for the selected compounds and total filler volume fraction and CB/silica ratio, there is an optimum value for the silane-to-silica ratio (13.3%). Moreover, it was also shown that the numerical technique presented in this work provides a practical framework for assessing the dynamic properties of the compounds without the need to perform dynamic tests.

This study aims to evaluate the feasibility of embedding coconut fibre (CF) as reinforcement into polylactic acid (PLA) for the fabrication of bio-composites using material extrusion-thermal reaction bonding of polymer (MEX-TRB/P) 3D printing. Traditional natural fibre-reinforced composites rely on premixed filaments or other additive manufacturing (AM) techniques, which limit control over fibre placement and distribution. As sustainability becomes an increasingly important focus in materials engineering, natural fibres and biodegradable polymers like PLA present a promising path toward eco-friendly manufacturing. However, no standardised method exists to manually integrate fibres onto polymer during MEX-TRB/P 3D printing. In this project, CFs were chemically treated using sodium hydroxide (NaOH) to remove surface impurities to improve fibre-matrix adhesion. The treated fibres were then oven-dried and embedded into the PLA matrix during the MEX-TRB/P 3D printing process via a new fabrication approach, where the print was paused at specific layers to insert fibre strands between layers of molten PLA. Each strand has four fibres, and the strands were placed perpendicular to the direction of the impact force. Five composite types were fabricated, which are neat PLA, 1-layer untreated, 3-layer untreated, 1-layer treated and 3-layer treated bio-composites. Impact strengths of the composites were determined using the Izod impact test. The results showed a significant increase in impact resistance with the inclusion of fibres. Compared to neat PLA (9.75 J/m), untreated 1-layer and 3-layer composites recorded 12.34 and 14.72 J/m, which showed a 26.6% and 51.0% increase compared to neat samples, respectively. Meanwhile, treated 1-layer and 3-layer composites reached 13.66 and 14.99 J/m, showing a 40.1% and 53.7% increase compared to neat samples, respectively. Fracture analysis confirmed ductile failure with strong fibre-matrix adhesion, especially in treated samples. This study introduces the first reported method of embedding CFs directly into an MEX-TRB/P 3D-printed PLA composite. The results demonstrate the potential of this newly proposed method to produce strong and sustainable composites.

This study investigated the preparation and self-association behavior in water of amphiphilic statistical copolymers, poly(vinyl alcohol-co-vinyl laurate) [P(VA/LA_x)] (x = 0, 7, 25, 32, and 41 mol%), composed of hydrophilic vinyl alcohol (VA) and hydrophobic vinyl LA units. These copolymers were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization. Due to their amphiphilic nature, P(VA/LA_x) formed micelles in aqueous solution. Dynamic light scattering (DLS) measurements showed that both the hydrodynamic radius (R_h) and light scattering intensity (LSI) values increased with increasing LA content, indicating that enhanced hydrophobicity promoted the formation of larger micelles. The copolymers exhibited unimodal size distributions with R_h values ranging from 57.3 to 100.4 nm, suggesting the formation of interpolymer aggregates driven by hydrophobic interactions among pendant lauryl units. Transmission electron microscopy (TEM) confirmed the formation of spherical micelles, with sizes consistent with R_h values. Static light scattering (SLS) measurements further revealed that the aggregation number increased with higher LA content. The critical micelle concentration (CMC), determined using a pyrene fluorescence probe, decreased with increasing LA composition, ranging from 3.3 to 0.62 × 10⁻³ g/L. These findings demonstrate that amphiphilic P(VA/LA_x) copolymers form stable interpolymer micelles in water, with tunable properties governed by their hydrophobic content.

The ability of polymeric materials to maintain their mechanical properties in humid environments is important for products across many industries, including paints and coatings, packaging, and personal care industries, amongst others. In this study, we utilize humidity-controlled dynamic mechanical analysis (RH-DMA) to evaluate the mechanical behavior of film-forming sulfopolyester polymers subjected to sustained stress in high-humidity environments. Our results demonstrate how these sulfopolyester polymer films respond to both oscillatory and creep deformations when exposed to high humidity. Our aim is to link their mechanical properties under elevated humidity conditions to their potential use as film formers that maintain hair curl retention in personal care applications. We propose the use of a force-controlled creep test using a 0.02 N load to simulate the gravitational force relevant to a 2 g hair sample. Under these testing conditions, we found the material with the highest Tg resulted in a 0.3% elongation after 5 h at 90% RH, which would suggest durable performance in hair styling applications. The results highlight the value of RH-DMA as a predictive tool for screening film formers in the development of personal care products.