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A lamellae-forming poly(ethylene oxide)-b-polystyrene (EOS) has been blended with a polystyrene homopolymer (PS) and a PS oligomer (PSO), respectively, to obtain miscible polymer blends (denoted as EOS/PS-32 and EOS/PSO-32, respectively). Both blends exhibit cylindrical microphase morphologies, with the PEO volume fractions being 0.32. The order–disorder transition temperatures (T ODT ) of...
Substituted poly(paraphenylene) derivatives (PX) have recently gained interest due to their unique properties [1–5]. They are amorphous thermoplastics with relatively modest glass transition temperatures (Tg∼150°C), are soluble in various common organic solvents, and yet possess the strongest mechanical properties of any amorphous thermoplastic [6]. However, the blend behavior of these polymers is...
Transmission electron microscopy (TEM) was used to examine the morphology of extruded thermoplastic starch/poly(ethylene-vinyl alcohol) (EVOH) blends. Both the starch and EVOH polymers were found to be very beam sensitive: the maximum allowable beam dosages for the crystalline fraction of both components are estimated at less than 3.5×10 −3 Ccm −2 at 200kV and room temperature. In...
Relaxation of disclination loops created during shear flow of a low molar mass and a polymer liquid crystal were monitored using a special shear stage with a videomicroscope. Loops in the polymer system generally displayed initially highly distorted contours. In the small molecule liquid crystal, the loop contours consistently exhibited very simple, generally convex shapes. In the polymer system,...
Polystyrene-polybutadiene-polystyrene triblock copolymers were roll-cast from toluene solutions to form globally oriented films. As-processed films, containing process-related residual stresses, were exposed to solvent vapours. Three solvents were used in this study: toluene, which is a non-preferential solvent for polystyrene and polybutadiene; methyl-ethyl-ketone, which is a preferential solvent...
Polystyrene-polybutadiene-polystyrene triblock copolymers were roll-cast from toluene solutions to form globally oriented films. Microstructural changes following thermal annealing of films with cylindrical and lamellar morphology were monitored using two-dimensional small angle X-ray scattering, transmission electron microscopy and thermomechanical analysis. The microdomains in the unannealed films...
High-resolution imaging of ordered polymers is described both theoretically and experimentally. The relationship between the actual three-dimensional specimen structure and the resultant two-dimensional image intensity distribution is developed using the multislice formalism. The influence of the electron optical conditions on the image is demonstrated with experimental data, as well as with image...
Low-voltage, high-resolution scanning electron microscopy (LVHRSEM) is a promising new technique for polymer morphological characterization, and provides complementary data to transmission electron microscopy, X-ray scattering and the scanning probe microscopies. Practically, lateral resolution on the order of 50 at 1.0 keV accelerating voltage can be obtained in polymer samples. The utility...
Blends consisting of a systematic compositional series of starch/poly(ethylene-co-vinyl alcohol) were studied by using capillary viscometry. Three different types of starches were used: waxy maize, a starch containing essentially 100% amylopectin; native corn, possessing approximately 70% amylopectin and 30% amylose; and a treated, high-amylose starch, consisting of approximately 30% amylopectin...
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