Advances in Polymer Technology最新文献

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.

Aerogel-modified polyamide 6 draw textured yarns (AE/PA6 DTYs) were prepared through melt spinning and subsequent drawing processes. The influence of draw temperature on the structural characteristics and mechanical properties of AE/PA6 DTYs were thoroughly investigated. The results demonstrated that the drawing process significantly improved the molecular the orientation and crystallinity of AE/PA6 DTYs. When the draw temperature was set at 148°C, the AE/PA6 DTY exhibited a higher content of hydrogen-bonded groups, an increased proportion of the α-form crystals, and enhanced crystallinity. These structural features contributed to superior tensile strength and crimp performance compared to samples processed at draw temperatures ranging from 143 to 173°C. Additionally, at this optimal draw temperature, the crimp contraction and crimp stability reached 51.62% and 66.69%, respectively, with a tensile strength of 4.36 cN/dtex. These findings provide meaningful insights and practical references for the optimization of the false twist texturing process for AE/PA6 DTYs.

Polymer–lipid hybrid (PLH) nanoparticles have become an appealing therapeutic delivery system owing to their special properties. These nanoparticles are made with polymer and lipid components and have garnered significant interest across therapeutic applications. The combined properties of the polymers and lipids enable improved drug delivery by enhancing the stability, biocompatibility, and controlled drug release of the nanoparticle. The versatility of this form of drug carrier, including biomimetic and biocompatible features, allows the encapsulation of a wide range of therapeutic agents, including hydrophilic and hydrophobic compounds, proteins, and nucleic acids. These drug carriers can be modified and adapted to target the desired site of action, specific cells, and tissues, while minimizing the possibility of off-target and adverse effects. Thus, this review provides an in-depth analysis into PLH nanoparticles as a novel delivery system, their inherent characteristics, the functionalization strategies, and their wide applications, while providing their potential for future possibilities.

Drug-eluting embolic microspheres are receiving increasing attention in transarterial chemoembolization (TACE), which is one of the most important approaches for the treatment of unresectable hepatocellular carcinoma (HCC). However, currently most commercial microspheres are radiolucent and their position in vivo needs to be indirectly monitored by X-ray angiography. In addition, microspheres reflux may cause nontargeted embolism. The aim of this study is to develop an inherently radiopaque embolic agent capable of delivering drugs and enhancing the embolic effect. In this study, using emulsification (S/W/O) and photocrosslinking, the mixture of methacrylated polyvinyl alcohol (PVAMA), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and barium sulfate was prepared into BaSO₄/PVA/AMPS beads. Barium sulfate act as computed tomography (CT) contrast agent, while sulfonic acid groups give the hydrogel beads drug loading and sustained release properties. The embolic performance of beads is enhanced by loading etamsylate. The results indicate that the prepared beads are radiopaque, biocompatible, with good drug sustained release performance. In vivo embolization and imaging properties were demonstrated by a rabbit ear central artery embolization model.

Additive manufacturing (AM) via material extrusion (MEx) offers customizable, cost-effective routes to patient-specific bone scaffolds, but balancing mechanical performance, production efficiency, and pore architecture in biodegradable composites remains challenging. In this study, we compounded 12 wt% silicon into polylactic acid (Si–PLA) filament and evaluated 12 MEx parameter clusters varying nozzle temperature (200–220 °C), bed temperature (70–90°C), infill patterns (hexagonal/line/triangular), infill density (60%–80%), print/travel speeds (40–60 mm/s), and firstlayer thickness (2–4 mm) using a SpiceLogic analytic hierarchy process (AHP) framework. Nine criteria spanning estimated vs. actual print time, ultimate tensile/flexural strength and moduli, and morphological quality (pore uniformity, surface defects, and infill fidelity) were weighted and ranked. The A4 cluster (200°C/70°C, line infill, 60%, 60 mm/s speeds, and 2 mm layer) emerged as optimal, delivering a 4.3 MPa tensile strength (+12%) and 17.2 MPa flexural strength (+15%) while reducing print time by 10%. Sensitivity analysis confirmed ranking robustness across ±10% weight variations. This decision science approach not only outperformed traditional Taguchi/response surface methodology (RSM) methods in multiresponses’ trade-off but also provides a scalable pathway for translating Si–PLA scaffold fabrication from lab to commercial production.

Hybrid jute–banana fiber-reinforced recycled high-density polyethylene (rHDPE) composites present a sustainable alternative for achieving improved mechanical performance and ecological durability. This study addresses the challenge of simultaneously optimizing flexural and impact properties along with structural integrity by employing a novel (0°/90°/0°/90°) stacking configuration using both plasma-treated and untreated fiber preforms. Composites were fabricated through compression molding, placing rHDPE sheets strategically within a four-layer fiber stack and applying 5-ton pressure at 160°C for 15 min, followed by a 24-h curing period. Plasma treatment drastically influenced the adhesion of fiber and matrix, leading to an increased impact strength and altered behavior of water absorption. The greatest impact strength of 31.86 kJ/m²—a 45.4% improvement over its untreated counterpart—was found in the plasma-treated hybrid composite (plasma jute–banana composite [PJBC]) with a 7.6% flexural strain, signifying improved energy dissipation and ductility. However, flexural strength in hybrid composites decreased marginally (from 21.3 to 20.3 MPa) due to increased surface brittleness. Plasma treatment improved water absorption in jute composites (0.13%) via increased porosity, but hybridization minimized the effect to yield balanced moisture absorption and mechanical properties. The synergistic combination of jute stiffness and banana flexibility in hybrid form, with plasma-induced surface activation, resulted in composites with optimal structural integrity and sustainability. These findings demonstrate the viability of plasma-treated hybrid rHDPE composites for resource-efficient application in packaging, automotive, and construction sectors, in line with the goal of the circular economy.