Journal of Applied Polymer Science最新文献

In this study, a novel boron-containing silicone elastomer (TBEB) was successfully fabricated using an o-carborane-modified crosslinker (BTPW) synthesized via electrophilic bromination and Heck coupling reactions. Compared with conventional tetraethyl orthosilicate (TEOS) crosslinked silicone rubber, the TBEB series exhibited remarkable improvements in tensile strength, elongation, and thermal stability. The optimized sample (TBEB-5) achieved a tensile strength of 1.45 MPa, an elongation of 467%, and a 17% increase in char yield relative to the control sample. Thermogravimetric analysis (TGA) revealed that the decomposition temperature (Td₅) of the TBEB series exceeded 408°C, while differential scanning calorimetry (DSC) confirmed enhanced chain rigidity and superior thermal resistance. Morphological characterization by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) indicated homogeneous dispersion of the crosslinker and a dense, well-organized network structure. Furthermore, the TBEB elastomers exhibited outstanding high-temperature aging resistance, maintaining 74% of their mechanical strength after 12 h at 200°C. Upon pyrolysis, the o-carborane units promoted the formation of a dense Si–O–C/B–O–Si ceramic-like network, improving ceramic yield and microstructural uniformity. Overall, this study provides an effective molecular design strategy for developing high-performance, heat-resistant silicone elastomers and polymer-derived ceramics with excellent structural integrity and long-term thermal stability.

This study develops a tunable bio-based epoxy platform by converting commercially available palm oil into an epoxy-functional renewable modifier and systematically linking processing parameters to final material performance. The epoxidation of palm oil is optimized using response surface methodology (RSM) by varying temperature (45°C–65°C) and reaction time (2–6 h), and the optimum conditions are identified as 64.56°C and 5.91 h in a PID-controlled reactor. Under these conditions, a maximum epoxidation efficiency of 80.98% is achieved with excellent model reliability (R ² = 0.9918, adjusted R ² = 0.9886, C.V. = 0.4575%). The resulting modified palm oil (MPO) is incorporated into a commercial epoxy resin at 0wt%, 15wt%, 30wt%, and 45wt% and cured to form sustainable epoxy networks. Characterization demonstrates that increasing MPO content progressively decreases bulk density (±4 to 6 kg/m³), Shore D hardness (±2 to 3), tensile strength (±1 to 2 MPa), thermal conductivity (±0.002 to 0.004 W/m K), and dielectric constant (±0.02 to 0.04), while significantly increasing elongation at break (±0.8% to 1.5%). These trends indicate a controlled transition from rigid to ductile behavior due to dilution of the aromatic epoxy network by flexible aliphatic chains and a corresponding reduction in crosslink density. FTIR spectroscopy confirms successful epoxidation through the loss of C=C bands and the appearance of epoxy C–O–C vibrations, whereas SEM reveals homogeneous morphologies at low MPO levels and phase separation at higher loadings. Curing kinetics slow with increasing MPO, reaching up to 48 h at 55°C compared with 24 h for neat epoxy. Overall, this optimized and scalable route enables the design of eco-sustainable epoxy materials with tailored mechanical, thermal, and electrical insulation properties suitable for coatings, adhesives, and lightweight insulation applications.

The development of large-tow carbon fibers, valued for their low cost and processability, remains a global research priority. This study systematically investigates the applicability of process conditions optimized for 25 K PAN-based carbon fibers to the production of 50 K large-tow fibers, focusing on their structural evolution and correlated performance. Thermal analysis revealed similar thermal behavior for both fiber types, evidenced by comparable initial stabilization temperatures, which is attributed to their identical precursor composition. However, density testing and morphological analysis (SEM/OM) reveal that 50 K fibers exhibit greater stabilization sensitivity and more pronounced core-shell structural differences during stabilization—their core indentation depth increases by 16% compared to 25 K fibers (128 vs. 110 nm). This structural non-uniformity is directly correlated with uneven heat distribution during the exothermic stabilization process. Despite these structural differences, both fibers demonstrated excellent performance stability. Composite material testing results indicate that performance fluctuations for both types can be controlled within 4%. In summary, this study confirms that existing 25 K process conditions can be effectively extended to 50 K large-tow carbon fibers production. It provides critical theoretical and technical support for scaling up efficient manufacturing while maintaining performance standards.

Cellulose nanofiber (CNF) based films usually suffer from poor water resistance and low wet strength, so it is highly desired to fabricate CNF-based films with high wet strength and additional functions to promote their applications. Herein, UV-blocking, antibacterial and antioxidant CNF-based films with high wet strength were prepared by using surface-modified cellulose nanocrystal (mCNC) as novel nanocrosslinker and naturally occurring tannic acid (TA) as multifunctional additive. Relying on its grafted polyacrylamide chains, mCNC served as an effective nanocrosslinker for both dry and wet CNF films, thereby enhancing both dry and wet strength of the film. The optimum CNF/mCNC composite film showed a dry tensile strength of 95 MPa and wet tensile strength of 17 MPa, which are 2.16- and 5.67-fold higher than pure CNF film, respectively. Further introduction of TA endowed CNF/mCNC/TA composite films with outstanding UV-blocking (near zero transmittance at 200–365 nm), antibacterial and antioxidant capacity, but at the cost of reduced mechanical performance due to its plasticizing effect. However, wet CNF/mCNC/TA composite films with moisture contents of 62%–64% still showed an utmost tensile strength of 9.5 MPa. Hence, a combination of high wet strength and multifunction makes the developed CNF/mCNC/TA composite films promising candidates for bio-based active food packaging.

A series of copolymerized Poly(aryl ether ketone) (co-PAEK) materials were synthesized through the copolymerization of hydroquinone (HQ), phenolphthalein anilide (PPA), and 4,4′-difluoro diphenylmethanone (DFBP). When the feed ratio of HQ to PPA varied from 0:10 to 5:5, the resulting copolymers were amorphous and showed good solubility in organic solvents. While, when the HQ to PPA ratio reached 7:3 or higher, the copolymers exhibited a semi-crystalline structure. By incorporating bulky and non-coplanar side groups into the backbone of polyetheretherketone (PEEK), the glass transition temperature (T _g ) significantly increased from 143°C to 246°C, and the heat deflection temperature (HDT) rose from 151°C to 237°C. The creep tests conducted at 150°C demonstrated that the co-PAEKs possess superior dimensional stability compared to PEEK. These enhanced properties suggest that the co-PAEKs have potential applications in areas such as polymer bearings and gears.

With the development of fluorinated waste treatment and the extraction of metals such as rare earths, high-density F⁻ wastewater becomes a potential threat. Compared to inorganic adsorbents for F⁻ removal with high cost due to agglomeration, this paper firstly utilizes maleic anhydride to control pH and achieves cross-linked PVA/PVP as polymer matrix and in situ synthesized Al(OH)₃ (ATH) as inorganic particles simultaneously, and obtains cross-linked ATH/PVA/PVP composite films with good mechanical property and excellent F⁻ removal capability. With the increasing ATH contents of ATH/PVA/PVP composites, the initial decomposition temperature improves from 253°C to 262°C. The SEM shows that the in situ synthesized ATH can be relatively evenly distributed on the surface and inside the ATH/PVA/PVP composite with a diameter of 8–30 μm. For the ATH/PVA/PVP composite, the most suitable pH for F⁻ adsorption is 5, and the adsorption capacity can reach 34.9 mg/g, and the F⁻ removal efficiency can reach 98.07%. The F⁻ removal of ATH/PVA/PVP composite can still remain 79.8% after five times regeneration, and interfering ions such as Cl⁻, NO₃ ⁻ have little effect on the F⁻ removal. The Young's modulus and tensile strength of the ATH/PVA/PVP composite can remain 6.2 GPa and 10.1 MPa even at 25 wt% ATH contents.

This study proposes a recycling strategy utilizing waste plastic bottles (PET bottle bodies and PE caps) to successfully fabricate a bilayer composite film, PET/(PE–TiO₂), which exhibits excellent passive radiative cooling performance and enhanced mechanical properties. The upper layer, consisting of highly reflective PET nanofibers fabricated via electrospinning, achieves a high solar reflectance (> 96%) across the solar spectrum (0.3–2.5 μm). The lower layer, a PE–TiO₂ composite prepared by melt blending, enhances the overall mechanical strength of the material. Systematic characterization demonstrates that the PET/(PE–TiO₂) bilayer film maintains high optical performance while significantly improving mechanical strength (breaking strength increased by > 5-fold) and thermal stability (decomposition temperature > 400°C). Both theoretical calculations and experimental validation confirm that the material achieves a net cooling power exceeding 100 W/m² under standard solar irradiation (1 kW/m²). Practical applications demonstrate surface temperature reductions of approximately 10°C for the human body and 5.3°C for electronic devices. This work not only achieves efficient synergistic recycling and value-added utilization of PET and PE but also provides a new approach for developing low-cost, high-performance, and environmentally friendly passive cooling materials, with broad application prospects in personal thermal management, electronic thermal regulation, and building energy efficiency.

Carboxylic nanocellulose (Car-SRNC) was successfully isolated from seaweed residue (SR) via aqueous citric acid (CA) pretreatment followed by ultrasonic disintegration, with the objective of enhancing the mechanical performance of polyvinyl alcohol (PVA) composite films. Statistical analysis revealed a strong positive linear correlation between the carboxyl content of Car-SRNC and both its yield and the mechanical strength of Car-SRNC/PVA films (Pearson's r ≈ 0.97, R ² ≈ 0.95), whereas no significant correlation was observed with CNC content. Based upon preliminary single-factor experiments, a systematic optimization of process parameters was performed using a three-level five-factor central composite design integrated with response surface methodology to evaluate the interactive effects of five critical variables: catalyst/SR ratio (0.5–1.5 g/100 g), CA concentration (75%–85%), pretreatment temperature (110°C–130°C), pretreatment time (4–8 h), and liquid–solid ratio (25–35 g/g). The developed models demonstrated high predictive accuracy, as indicated by a coefficient of determination of 0.9517, confirming their reliability for process prediction and optimization. Under the optimized conditions—catalyst/SR ratio of 0.98 g/100 g, CA concentration of 82.8%, pretreatment temperature of 122.5°C, pretreatment time of 7.5 h, and liquid-to-solid ratio of 30.8 g/g—the maximum carboxyl content of Car-SRNC reached 7.20 mmol/g, with a corresponding yield of 64.3%. When incorporated as a reinforcing agent, Car-SRNC with high carboxyl content significantly enhanced the tensile strength, tensile strain, Young's modulus, and toughness of the composite film by 53.82%, 13.53%, 173%, and 180%, respectively, compared to neat PVA films. This study presents a scalable and sustainable approach for the valorization of SR, a major byproduct of the alginate extraction industry.