聚醚砜的磺化与热性能

以浓硫酸为溶剂 ,氯磺酸为磺化剂对聚醚砜 (PES)进行了磺化 ,制备了不同磺化度的磺化聚醚砜 (SPES)。探讨了反应的影响因素 ,分析了 SPES的热稳定性。结果表明 SPES的 Tg较 PES升高 ,随着磺化度的增加 ,SPES的降解温度降低。     

Phase separation in non-solvent/dimethylformamide/polyethersulphone and non-solvent/dimethylformamide/polysulphone systems

The cloud point curves for the ternary solutions non-solvent/dimethyl-formamide/polyethersulphone and non-solvent/dimethylformamide/polysul-phone were determined by a titration technique, at 303 K. In both systems the following order of increasing non-solvent content at the cloud point was obtained: water < methanol < ethanol < 1-propanol < acetone < carbon tetrachloride. For each non-solvent the cloud point curve for the PES system occurred at higher non-solvent concentrations than for the corresponding PSN system.     

Flexible organic thin-film transistors using single-walled carbon nanotubes as an activated channel

We report on the fabrication of organic thin-film transistors (OTFTs) with a spun cross linked poly-4-vinylphenol (PVP) dielectric on a polyethersulphone (PES) flexible substrate. To improve the electrical performance of OTFTs, we employed a random single-walled carbon nanotubes (SWNTs) network as a carrier transfer underlay without sacrificing the flexibility of the TFTs. The random SWNTs showed that they can act as a semiconducting channel and conduction path to shorten the channel length in our TFTs. The flexible thin-film transistors (TFTs) with a random SWNTs/pentacene bilayer as an active channel exhibited an improved saturation field effect mobility (µ_sat) of 2.6 × 10^− 1 cm²/Vs compared to that of TFTs without the SWNTs underlay, while creating only a minor reduction of the current on/off ratio.     

Phase separation in epoxy resins containing polyethersulphone

Scanning electron microscopy and dynamic mechanical spectroscopy have been used to study phase separation of dissolved polyethersulphone (PES) from trifunctional and tetrafunctional epoxy resins during curing. No phase separation was observed at high concentrations of the tetrafunctional resin. Observations of nodules on fracture surfaces, and of multiple peaks in the dynamic mechanical spectra provided evidence for a separate, crosslinked, PES-rich phase in the remaining materials. Despite the variety of morphologies obtained in mixtures of PES with different hardeners and resins, modulus and fracture toughness showed little dependence upon composition.     

Influence of solid lubricants and fibre reinforcement on wear behaviour of polyethersulphone

Polyethersulphone (PES), is an amorphous, brittle and high temperature engineering thermoplastic. Two composites of PES containing short glass fibres (GF) and solid lubricants viz. PTFE and MoS₂; and two composites containing short carbon fibre (CF) [30% and 40%] were selected for the present studies. Compositional analysis of selected materials was done with various techniques such as gravimetry, solvent extraction and thermal analysis viz. thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). These materials were studied for adhesive and abrasive wear performance by sliding against a mild steel disc and silicon carbide abrasive paper respectively, under different loads. It was observed that GF reinforcement along with incorporation of solid lubricants (PTFE and MoS₂) enhanced the wear performance of PES by an order of two. In the case of solid lubricants, PTFE proved to be more beneficial than MoS₂. CF reinforcement, however, proved to be the most effective in enhancing wear performance of PES. PES reinforced with 40% CF exhibited a specific wear rate in the order of 10⁻¹⁶m³/Nm which is considered to be very good for the thermoplastic composite. In the case of abrasive wear behaviour, however, incorporation of fibres or solid lubricants deteriorated the performance of the neat matrix. SEM was employed to investigate the wear mechanisms.