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Film Casting (film + casting)
Selected AbstractsPreparation and characterization of biaxially oriented films from polybutylene terephthalate based thermoplastic elastomer block copolymersPOLYMER ENGINEERING & SCIENCE, Issue 11 2000Hang Li Film casting and biaxial stretching of a series of polyester thermoplastic elastomers (TPEs) were studied. Biaxial orientation in the stretched films was characterized by wide-angle X-ray diffraction and birefringence measurements. Biaxial orientation factors were determined. The X-ray diffraction and birefringence clearly indicated the development of planar biaxial orientation in the stretched films with biaxial stretching. The phenyl groups in the stretched PBT and TPE films gradually became more parallel to the film surfaces with increasing biaxial orientation. The lower the PBT content in the stretched TPE films, the lower the planar biaxial orientation achieved. The , form of crystalline PBT was found only in the stretched PBT films, but not in the TPE films. [source] Nonisothermal two-dimensional film casting of a viscous polymerPOLYMER ENGINEERING & SCIENCE, Issue 8 2000Spencer Smith A model is presented for simulating two-dimensional, nonisothermal film casting of a viscous polymer. The model accommodates the effects of inertia and gravity, and allows the thickness of the film to vary across the width, but it excludes film sag and die swell. Based on the simulation results, three factors are shown to contribute to reducing neck-in and promoting a uniform thickness: the self-weight of the material, for low viscosity polymers; nonuniform thickness and/or velocity profiles at the die; and cooling of the film, especially when localized cooling jets are employed. [source] Polycarbonate/SiC nanocomposites,influence of nanoparticle dispersion on molecular mobility and gas transport,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 2-3 2005Martin Böhning Abstract Plasma synthesized silicon carbide (SiC) nanoparticles were dispersed in dichloromethane/poly(bisphenol-A-carbonate) (PC) solutions by high power ultrasonification. Samples were then prepared by film casting under well adapted preparation conditions. The influence of the SiC nanoparticles on the molecular mobility of the PC is studied by dielectric relaxation spectroscopy. No effect on the cooperative segmental mobility (glass transition) was detected. But the relaxation region corresponding to localized fluctuations is strongly broadened and the activation energy is reduced with increasing nanoparticle concentration. The most significant change was observed in the relaxation region between , - and , -process. The gas transport properties of these nanocomposite films are characterized in terms of permeability, diffusivity and solubility. Results can be interpreted based on an altered local free volume distribution and a change of molecular mobility of the polymer matrix near the nanoparticle surface which is in agreement with the dielectric results. Concentration dependent CO2 permeation experiments reveal a significant reduction of plasticization effects in the nanocomposites compared to the pure PC. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||