Use of reactive polyetherimide to modify epoxy thermosets. I. Synthesis of an amino-grafted polyetherimide

Enhancing the Mechanical and Thermal Properties of Epoxy Resin via Blending with Thermoplastic Polysulfone

Efficient enhancement of the toughness of epoxy resins has been a bottleneck for expanding their suitability for advanced applications. Here, polysulfone (PSF) was adopted to toughen and modify the epoxy. The influences of PSF on the mechanical and thermal properties of the epoxy resin were systematically studied by optical microscopy, Fourier transform infrared spectrometer (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyzer (TG), dynamic mechanical thermal analyzer (DMA), mechanical tests and scanning electron microscope (SEM). The dissolution experimental results showed that PSF presents a good compatibility with the epoxy resin and could be well dissolved under controlled conditions. The introduction of PSF was found to promote the curing reaction of the epoxy resin without participating in the curing reaction and changing the curing mechanism as revealed by the FT-IR and DSC studies. The mechanical properties of PSF/epoxy resin blends showed that the fracture toughness and impact strength were significantly improved, which could be attributed to the bicontinuous phase structure of PSF/epoxy blends. Representative phase structures resulted from the reaction induced phase separation process were clearly observed in the PSF/epoxy blends during the curing process of epoxy resin, which presented dispersed particles, bicontinuous and phase inverted structures with the increase of the PSF content. Our work further confirmed that the thermal stability of the PSF/epoxy blends was slightly increased compared to that of the pure epoxy resin, mainly due to the good heat resistance of the PSF component.

Porous membranes based on poly(ether imide)-graft-poly(vinyl acetate) as a scaffold for cell growth

A series of poly(ether imide)-graft-poly(vinyl acetate) copolymers with different molecular weights were synthesized successfully and characterized using Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimeter, thermogravimetric analysis, and X-ray photoelectron spectroscopy analyses. These copolymers were used to fabricate honeycomb-structured porous films using the breath figure templating technique. The surface topology and composition of the highly ordered pattern film were further characterized using a scanning electron microscopy. The results indicated that the poly(ether imide)-graft-poly(vinyl acetate) graft molecular weight ratio influenced the breath figure film surface topology. A model was proposed to elucidate the stabilization process of the poly(ether imide)-graft-poly(vinyl acetate)-aggregated architecture on the water droplet–based templates. In addition, cell viability has been investigated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test, and the cell morphology on the honeycomb-structured poly(ether imide)-graft-poly(vinyl acetate) porous film has been evaluated using a fluorescence microscope. This porous film is shown to be suitable as a matrix for cell growth.