Journal of Applied Polymer Science最新文献

A novel, industry-oriented strategy was developed to enhance flame retardancy in polyester fibers through a zinc phosphinate-based masterbatch. The masterbatch was prepared via twin-screw extrusion using 20 wt% Exolit OP950 and high-viscosity bottle-grade PET granules, selected to mitigate molecular degradation and preserve rheological integrity during melt-spinning. It was subsequently incorporated into virgin fiber-grade PET at 3%, 5%, and 7 wt% concentrations to produce flame-retardant fibers. Rheological evaluations revealed pronounced shear-thinning behavior and increased elasticity with higher flame retardant (FR) loading, indicating improved melt strength and viscoelastic stability. Thermal analyses demonstrated enhanced char formation and reduced heat release, with residual carbon content rising from 5.7% in neat PET to 10.7% in the 7% FR sample. The limiting oxygen index (LOI) increased from 20.5% to 24.5%, and vertical burning tests confirmed a UL-94 V-2 rating with significantly reduced melt dripping. Mechanical testing showed that fibers maintained appropriate tenacity (2.98 g/den), although accompanied by reduced elongation at break, highlighting the trade-off between strength and ductility. SEM/EDX analysis confirmed uniform dispersion of FR particles and the presence of phosphorus and zinc. This approach provides a scalable solution for producing flame-retardant PET fibers without compromising industrial processability, while balancing mechanical performance and fire safety.

To leverage strong P/N synergistic effects to impart high flame retardancy to epoxy resin without compromising overall performance, a novel flame retardant, 6-(pyrimidin-2-ylamino)dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DAP), was synthesized by forming a P–N bond between 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and 2-aminopyrimidine. Its structure was confirmed by NMR and mass spectrometry. Non-isothermal DSC tests demonstrated that DAP acted as a co-curing agent with 4,4′-diaminodiphenylmethane for diglycidyl ether of bisphenol-A and enhanced the curing rate. DAP significantly enhanced the flame retardancy of the epoxy resin at a low loading of 4 wt% (0.40 wt% phosphorus), achieving a limiting oxygen index (LOI) of 32.1% and a UL-94 V-0 rating. It also reduced heat and smoke release. The results from dynamic mechanical analysis (DMA) and mechanical property tests showed that the epoxy resin containing 4 wt% DAP retained a glass transition temperature comparable to the neat resin, along with slight improvements in mechanical properties, including flexural strength and modulus, non-notched impact strength, and tensile strength. The analyses of UL-94, cone calorimetric test (CCT), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis/infrared spectroscopy (TGA/IR), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) revealed that the flame-retardant mechanism involved both a condensed-phase char barrier and gas-phase quenching and dilution effects.

Frequent oil spills and industrial oily wastewater discharges necessitate the development of high-performance, recyclable oil-absorbing materials, as traditional options suffer from low adsorption capacity and poor reusability. To address these limitations, this study developed crosslinked bacterial cellulose (BC) aerogels using 1,2,3,4-butanetetracarboxylic acid (BTCA) and sodium hypophosphite (SHP) as crosslinking agents. The aerogels were fabricated via freeze-drying and brief thermal esterification. By systematically optimizing BTCA content, the 10% BTCA formulation achieved a dense 3D network without crystalline precipitation, exhibiting high porosity (99.8%), minimal shrinkage (5.9%), and reduced pore size (2.2 nm). Crosslinking preserved the cellulose I structure but reduced crystallinity, as confirmed by FTIR and XRD. Thermal stability improved significantly, with residual mass at 600°C increasing from 21.8% to 39.0%. The aerogel demonstrated superior compressive resilience and structural stability in water, with oil absorption capacities of 115.4 g/g for paraffin oil, 98 g/g for engine oil, and 96 g/g for edible oil. Recyclability tests showed 84% retention after 20 ethanol cycles. This work provides a scalable, eco-friendly strategy for robust aerogels with multifunctional oil-absorption capabilities.

Due to the unique application environment of new energy vehicle charging piles, the cable sheath materials are subject to stringent requirements. Enhancing the flame retardancy of cable sheath materials while maintaining their mechanical and insulation properties is important. The cross-linked high-density polyethylene (HDPE)/ethylene propylene diene monomer rubber (EPDM) blend (TPV) is considered an excellent cable sheath material, combining desirable electrical insulation and environmental shielding properties. Here, an intumescent flame retardant (IFR) composed of ammonium polyphosphate (APP) and dipentaerythritol (DPER) was combined with zinc borate (ZB) to enhance the flame retardancy of TPV, and the optimal ZB loading was investigated. The results revealed that the sample “0.10ZB” with the loading ZB of 0.1 phr reached a limiting oxygen index (LOI) value of 24.4% and a UL94 V-0 rating. Cone calorimeter tests further demonstrated that 0.10ZB effectively reduced both the heat release rate (HRR) and total heat release (THR), indicating a significant improvement in flame retardancy. Moreover, the 0.10ZB composites also exhibited excellent mechanical and insulation properties, demonstrating a balanced property profile suitable for practical cable sheath applications.

Constructing hydrophobic coatings on transparent poly(methyl methacrylate) (PMMA) with integrated optical transparency and long-term stability remains a significant challenge. This study develops a multisite covalent anchoring strategy using perfluoroalkyl copolymers to simultaneously maintain high transmittance (> 90%) and durable hydrophobicity. Compared to conventional silane coupling agents—which reduced transmittance by 10% due to micron-scale agglomeration and suffered > 30° contact angle loss after environmental stress—the covalently anchored copolymer exhibits exceptional performance, retaining > 95% initial contact angle (Δ < 3°) through 10 wastewater exposures while preserving optical clarity. The stable covalent network formed via multipoint backbone bonding to PMMA surfaces minimizes coating delamination and eliminates light-scattering defects, enabling sustained hydrophobic stability under harsh conditions. This approach resolves the critical stability-transparency trade-off in silane-based modification and provides a viable paradigm for functionalizing optical polymer surfaces through engineered multivalent interfaces.

With the continuous growth in global electricity transmission demand, contamination flashover on high-voltage insulators has become a critical threat to grid stability, particularly, in rapidly industrializing regions. Although numerous studies have addressed the mechanisms and prevention strategies of flashover, quantifying the correlation between pollution and flashover occurrence, as well as establishing a scientific basis for effective prevention and maintenance strategies, remains highly important. This study investigates the flashover mechanism of composite insulators under polluted conditions, with a focus on the effects of contaminant composition, wetting behavior, and material properties. Through experimental measurements of the equivalent salt deposit density (ESDD), it was found that surface conductivity is highly sensitive to humidity and pollutants such as soluble salts. Using an optimized artificial contamination method, natural pollution accumulation processes were simulated, and the degradation of silicone rubber sheets under multiple flashover events was evaluated. The results indicate that the flashover voltage decreases significantly with increasing pollution severity and cumulative discharge events, while material damage intensifies with higher contamination levels. Molecular-level analysis further reveals the chemical degradation pathways and structural changes induced by flashover.

To address the detrimental low-temperature viscosity increase and flow impairment in oil-based drilling fluids caused by wax precipitation, this study designs and synthesizes a novel polymeric wax inhibitor featuring long alkyl chains and ester groups via two-stage copolymerization. Comprehensive characterization by FT-IR, ¹H NMR, GPC, and TGA confirms the molecular structure and thermal stability. Rheological measurements demonstrate that adding merely 2 wt% wax inhibitor suppresses viscosity escalation in both model waxy systems and wax-intruded drilling fluids. Crucially, the wax inhibitor preserves emulsion stability with demulsification voltages exceeding 2048 V post-wax intrusion. Mechanistic studies reveal molecular-level disruption of wax crystallization: alkyl chains anchor into wax crystals through structural similarity, while polar ester groups interfere with ordered stacking. This is evidenced by XRD showing reduced interplanar spacing and attenuated diffraction peaks, DSC confirming depressed phase transition enthalpy with low-temperature shoulder peaks, and SEM revealing collapsed non-network morphologies. The molecularly engineered copolymer thus effectively mitigates flow assurance challenges in deepwater and cryogenic drilling operations.

Cellulose nanofibers (CNFs) have attracted significant research interest owing to their remarkable features, including low density, outstanding durability, excellent thermal stability, large aspect ratio, extensive coverage and reactivity, eco-friendliness, and biodegradability, although they are highly flammable. This research employed rice husks as a sustainable source to develop and optimize flame-retardant nanocellulose (FR-NC) using a phosphorylation-based modification method. Comprehensive characterization and comparison were conducted on the surface chemistry, particle distribution, crystallization, thermal behavior, and flame-retardant ability of the produced CNFs. The FTIR, XPS, elemental, and zeta potential investigations verified the bonding of phosphorus molecules on the CNF's surface. Phosphorylation affected crystallinity but still resulted in a larger nanofiber diameter. The findings showed that the primary chemical structure of cellulose was unaffected by phosphorylation. The resulting CNFs retained the cellulose I crystallographic shape and exhibited higher absolute zeta potentials (> 40 mV) and nanometric diameters (< 100 nm). Moreover, the developed CNFs exhibited improved thermal stability and higher char-forming ability compared to crude cellulose at 800°C, along with a 70% increase in the limiting oxygen index (LOI) value. Furthermore, the addition of phosphate groups in CP₁ has also been shown to significantly increase flame retardancy, with less self-ignition (26 s) and more char formation (89%) compared to CP₀ (237 s and 5%, respectively). Finally, FR-NCs with different ratios of phosphorus-containing compounds can find applications as fillers or reinforcements in structural composites, electronic items, floor coatings, and packaging materials.

To increase the toughness of epoxy resin, an allyl-terminated furanylbenzoxazine (AFB) derived from eugenol was copolymerized with epoxy resin (E51). Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) analyses were used to examine the curing behavior of the blended resins. With increasing AFB content, the crosslinking density of the EP-AFB resins decreases, while the residual carbon yield (Y_c) of the epoxy resins after high-temperature combustion in a nitrogen atmosphere increases. The Y_c of EP-4AFB increased from the initial 14.92% to 20.21%. In addition, appropriate concentration of AFB could be conducive to improving the mechanical properties. The flexural and impact strengths of EP-1AFB resins were 3.5% and 81.3% higher than EP resins, respectively. The elongation at break and tensile strength of EP-3AFB resins were 91.2% and 68.4% higher than EP resins, respectively. Furthermore, the addition of AFB significantly modified both adhesive (lap shear strength and peel strength) and dielectric properties of the epoxy resins.

The corresponding relation between the thermo-oxidative aging level and the multiscale assessment of the properties for polyethylene is a challenging issue. A novel hybrid antioxidant, designated TiO₂-KH550-PA, was synthesized, and the influence of the filler on the thermal-oxidative aging behavior of polyethylene was investigated from multiple scales. The results show that the TiO₂-KH550-PA can provide a better synergistic protective effect for the thermo-oxidative aging resistance of polyethylene. Compared with pure polyethylene, the polyethylene containing TiO₂-KH550-PA has excellent anti-aging performance, including a decrease by 86.48% in the diffusion coefficient of O₂ molecule at 373 K, a decrease by 16.25% in the maximum displacement of O₂ molecule, and a decrease by 14.78% in the free volume fraction. The accelerated aging tests show that the TiO₂-KH550-PA filler can suppress the generation of chromogenic groups and inhibit the transfer reaction of free radicals, thus strengthening the thermo-oxidative aging resistance of polyethylene.