Advances in Polymer Technology最新文献

Piezoelectric polymer nanofibers are promising for wearable electronics due to their mechanical compliance and electromechanical responsiveness. Poly(vinylidene fluoride)-trifluoroethylene (PVDF-TrFE) is widely used for its ferroelectric β-phase and favorable piezoelectric properties, yet its limited elasticity hinders applications in soft bioelectronics. Electrospun PVDF-TrFE mats can stretch through fiber rearrangement but lack true elastic recovery unless molecular interactions and junctions are modified. Achieving nanofiber networks that are both stretchable and piezoelectrically stable under cyclic strain remains a challenge. Here, we report a strategy combining PVDF-TrFE with a small fraction of poly(ethylene glycol) bis(amine) (PEG-diamine) and thermal annealing to form fused nanofibrous mats with enhanced elasticity and stable piezoelectric output. The blended mats doubled the strain-to-failure (~30%) compared to pure PVDF-TrFE (~14%) and showed Mullins-like elastic recovery up to approximately 9% with reduced hysteresis. Piezoelectric response improved by approximately 25% in peak voltage (~150 mV), with greater signal stability. Structural analyses (Fourier-transform infrared [FTIR], differential scanning calorimetry [DSC], and X-ray diffraction [XRD]) confirmed increased β-phase content and selective cross-linking in amorphous domains without compromising ferroelectric order. This work demonstrates a scalable material-based approach to improve elasticity and durability in electrospun piezoelectric fibers, enabling stretchable and skin-conformable sensors for smart fabrics, wearable health monitors, and energy harvesting.

Skin grafting is a widely used technique for treating extensive skin injuries such as chronic ulcers, wounds, and burns. Traditional grafting techniques face various challenges, including limited availability, risk of infection, donor site morbidity, and immune rejection. Due to their tailored properties, synthetic skin grafts offer a promising alternative solution to these challenges. This study aims to fabricate polymer blends by integrating the bioactivity of chitosan, derived from natural polymer (chitin), with the mechanical resilience of synthetic polymers—poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG). Two Polymer blends, 30CHI:70(PVA/PEG) and 20CHI:80(PVA/PEG), were prepared through physical crosslinking. The pH-responsive and hydrophilic behavior of the blends was evaluated in phosphate-buffered saline (PBS) solution to mimic physiological conditions. Different characterization tests, including tensile testing, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), pH sensitivity, contact angle, antibacterial, cytotoxicity, and thermal analysis, revealed that the 20CHI:80(PVA/PEG) blend demonstrated mechanical resilience, superior hydrophilicity, and pH responsiveness compared to other blends. This polymer also exhibited low shrinkage, controlled swelling, and excellent biocompatibility, making it a suitable candidate for skin graft applications. However, in vivo evaluations are needed to further validate the clinical potential of this blend. The findings of this study highlight the potential of material integration for developing biocompatible, versatile, and viable polymer blends for advanced tissue engineering applications.

Developing new materials by recovering waste materials in the polymer reinforcement process helps to protect the environment and ensure a circular economy for these waste materials when they reach the end of their life cycle. This study shows the possibility of developing a new composite with bilinga and epoxy resin waste. Composites were realised by using cold pressure moulding technique with different pressures, particle sizes and reinforcement rate. Physical tests were carrying out to determine moisture content, water absorption rate and density by using a gravimetric method. Three-point bending tests were used to determine flexural Young modulus and maximum break stress. Asymmetric Hot plane method with insulated rear face were used to determine thermal conductivity of composites. Results obtained show that moisture content varies from 2.3% to 6.65% and water absorption rate from 61% to 191%. These results allow us to say that this composite material has a hydrophilicity character. Young’s modulus of these materials is between 117 and 1951 MPa. Breaking stress of these composite materials is between 0.5 and 12.5 MPa. Results show that increasing compaction pressure also increases the mechanical properties of composite, as shown by standard EN312 for used in dry and humid environments. The thermal conductivity of the composite in between 0.18 and 0.27 W m⁻¹ K⁻¹. These results confirm that the composite materials produced can be used in furniture manufacturing, thermal insulation for homes and ceilings, and the development of sandwich materials.

Innovative advancements in polyolefin chemistries are critically important to develop industrial applications that require an ability of either superior performance levels or minimal expense. While temperature rising elution fractionation (TREF) is a well-established analytical technique for characterising polyolefin heterogeneity, its use as a preparative tool for actively engineering properties remains underexplored. This research investigated the effects of continual extraction of fractions of copolymers, through either molecular fractioning or selective fractions, for propylene–1-pentene copolymers, on structure–property relationships. Moving beyond the established correlation between elution temperature and comonomer content, this study demonstrates how the strategic subtraction of amorphous-rich or crystalline-rich fractions can systematically tune the bulk material’s properties. Conditions were created to allow for systematic removal of selected fractions while characterising the remaining polymer by density-based fractional crystallinity, differential scanning calorimetry (DSC), ¹³C NMR, micro-hardness testing and positron annihilation lifetime spectroscopy (PALS). This study has demonstrated the potential to directly enhance the crystallinity and microhardness of the copolymer by selectively removing amorphous-rich fractions. More importantly, it establishes ‘selective fraction removal’ as a proof-of-concept for a new materials design strategy. In contrast, it is not very likely that removing fractions of highly crystalline-based polymer will create improvements to properties. In addition, this study has shown that selectable fractions provide an effective means to tune polymer properties at the laboratory scale. While the method demonstrates potential, its industrial scalability would require further research and methodological adaptation.

Poly(3-hydroxybutyrate) (PHB) is a biodegradable polymer that represents a potential replacement for some traditional plastics. The properties of PHB are impacted by many variables including its molecular weight. There are many applications that can be fulfilled by low molecular weight PHB (LMWPHB). We have investigated the use of potassium phosphate (K₂HPO₄) as a catalyst for degrading PHB. Potassium phosphate was demonstrated to degrade the polymer in a concentration-dependent manner. Low concentrations (0.2%) of K₂HPO₄ decreased the thermal stability of the polymer and rapidly reduced the molecular weight. Comparisons to related chemicals (potassium sulfate, potassium chloride, calcium phosphate, and sodium phosphate) demonstrated that the K₂HPO₄ had the greatest effect on thermostability. Low amounts of K₂HPO₄, but not other salts, led to a decrease in the crystallization temperature and bimodal melting behavior, indicative of the formation of smaller crystallites. This is the first report of the use of K₂HPO₄ to convert PHB into lower molecular weight species.

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.