Poly(ethylene oxide) (PEO)-based composite solid electrolytes (CSEs) have attracted considerable attention owing to their excellent flexibility and interfacial compatibility. However, their practical application is limited by the poor dispersion of inorganic fillers and weak organic-inorganic interfacial interactions, which lead to severely impeded ion transport. Herein, we proposed a synergistic design strategy based on oxygen-vacancy-rich aligned nanofibers to construct continuous directional ion transport pathways and enhance organic-inorganic interfacial interactions. This resulting CSE delivered a high ionic conductivity of 0.79 mS & centerdot;cm(-1) at 60 degrees C, a Li+ transference number of 0.74, and a wide electrochemical window of 5.2 V. Moreover, the Li symmetric cell demonstrated excellent cycling stability with 1500 h at 0.5 mA & centerdot;cm(-2), while the LFP cell retained 89% capacity retention after 200 cycles. [GRAPHICS]
To address the issues of uncontrollable sulfonic acid group sites, susceptibility of the polymer main chain to degradation in traditional post-sulfonation processes, and the intrinsic insufficient oxidative stability of membrane materials, this work designed and synthesized a sulfonated diphenyl-biphthalazine-dione monomer (SDBD-Na). The sulfonic acid groups were introduced onto the side benzene rings at the monomer stage. Using SDBD-Na, 4-(4 '-hydroxyphenyl)-2,3-phthalazinone (DHPZ), and 4,4'-difluorodiphenyl ketone (DFK) as monomers, a series of sulfonated poly(aryl ether ketone)s containing diphthalazinone units with ether-free linkages in the hydrophilic segments (S-PDPEKs) were prepared via high-temperature solution polymerization. The obtained polymers exhibited intrinsic viscosities ranging from 1.18 dL & centerdot;g(-1) to 2.77 dL & centerdot;g(-1), ion exchange capacities (IEC) between 0.89 and 1.46 mmol & centerdot;g(-1), and tensile strengths between 51 and 93 MPa, demonstrating excellent mechanical properties. At 80 degrees C, the water uptake of S-PDPEKs membranes ranged from 11.2% to 24.3%, and the swelling ratio was significantly lower than that of Nafion 212, indicating good dimensional stability. In Fenton's reagent at 80 degrees C, the breaking time of S-PDPEKs membranes ranged from 6.3 h to 18 h, and the dissolution time ranged from 14.5 h to 40.0 h. Compared with the materials modified by post-sulfonated process (b-SPDPESs, SPDPEKKs), their oxidative stability was significantly improved. The proton conductivity of S-PDPEKs membranes ranged from 15.0 mS & centerdot;cm(-1) to 81.3 mS & centerdot;cm(-1). When assembled into hydrogen-air fuel cells, the S-PDPEKs membranes achieved a maximum power density (P-max) of 156.7 mW & centerdot;cm(-2).
Poly(lactic acid) (PLA) is a typical bio-based biodegradable polyester, but its slow crystallization rate and poor heat resistance limit its applications in high-performance fields. Constructing stereocomplex crystals (SC) is one effective way to improve PLA's crystallization and thermal properties. However, direct physical blending of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) tends to cause phase separation, making it difficult to prepare materials with high SC content. In this work, a series of poly(D-lactide)-b-poly(glycolic acid) (PDLA-b-PGA) block copolymers were synthesized via ring-opening polymerization and blended with PLLA. The effects of block copolymer loading and the molecular weight of PGA blocks (Mn,PGA) on the crystallization behavior and formation rule of SC in the blends were systematically investigated. The results showed that PLLA/ PDLA-b-PGA blends could simultaneously form both PLLA homocrystals (HC) and SC, with SC crystallizing before HC. The PGA block delays SC crystallization and lowers its melting point due to steric hindrance, but Mn,PGA, can precisely control the SC content in the system. When Mn,PGA exceeds 5000 g/mol, PGA blocks provide heterogeneous nucleation sites, significantly increasing the amount of SC formed in the blend
Silane-modified liquid polybutadiene (SiLPB) with different 1,2-vinyl contents were prepared to study the effect of 1,2-vinyl content on rubber properties. H-1-NMR, FTIR and GPC results confirmed that the samples SiLPB had similar silane contents and molecular weights. DSC results showed that, as the 1, 2-vinyl content in SiLPB was increased from 5% to 80%, its glass transition temperature was increased from - 87 degrees C to - 26 degrees C . Replacing 10 phr conventional aromatic oil (TDAE) with SiLPB effectively reduced the Mooney viscosity of the compounds, prolonged the scorch time and improved silica dispersion, while maintaining the similar curing time (t(90)) and physical-mechanical properties to that containing TDAE oil (C-Ref). Vulcanizates containing SiLPB with high 1,2-vinyl content (C-SiLPB60 and C-SiLPB80) exhibited better thermal-oxidative aging resistance, although their abrasion resistance was decreased by approximately 5% compared with C-Ref. In contrast, SiLPB with 1,2-vinyl contents below 45% showed no obvious effect on abrasion resistance. Dynamic mechanical analysis and rebound tests demonstrated that all SiLPB samples significantly reduced the tan delta value at 60 degrees C and increased the rebound resilience at 70 degrees C, indicating their potential to reduce rolling resistance. Meanwhile, the tan delta value at 0 degrees C was gradually increased with increasing 1,2-vinyl content in SiLPB, suggesting the potential to improve wet-skid resistance. These results indicate that regulating the 1,2-vinyl content in SiLPB provides a new strategy for balancing the performance of tire tread materials.
With the rapid advancement of artificial intelligence, the demand for new materials driven by emerging technologies has become increasingly urgent making the development of novel high-performance polymer mechanical sensing materials of significant scientific research importance. In this study, poly(lactic acid)/polyaniline (PLA/PANI) hybrid fibre membrane materials were prepared using electrospinning method. The effects of various electrospinning process parameters, including spinning voltage and PLA concentration, on fibre morphology were investigated to determine the optimal spinning conditions. Furthermore, we examined the preparation of PLA/PANI fibre membrane mechanical sensing materials by incorporating polyaniline. The results showed that the well-defined fiber morphology was obtained at a spinning voltage of 15 kV, a PLA mass fractions solution of 7.50% and a PANI mass fraction of 0.12% of the solution. Comparing the electrical properties of PLA and PLA/PANI fibre membranes showed that adding PANI significantly increased the electrical conductivity of the PLA fibre membrane. Research the stress-sensing properties of the material has revealed that PLA/PANI composites exhibit significant piezoelectric behavior. This is the first reported instance of using PLA and PANI to construct a flexible stress sensor, providing a viable approach for the future fabrication of polymer piezoelectric sensor devices
