The phase behaviour and the mechanical properties of binary blends composed of poly(ether ether ketone) and poly(ether sulphone) have been studied both in the amorphous state and after crystallization of poly(ether ether ketone).Differential scanning calorimetry and dynamical mechanical analysis clearly show the existence of phase separation in the blends. Density measurements confirm the absence of strong interactions between the blend components, as well as the slight effect of PES on the crystallization of PEEK.The mechanical properties of the quenched, amorphous blends remain surprisingly good in spite of the observed immiscibility, however, slowly cooled, crystalline blends appear as brittle materials. 相似文献
A case of bilateral facial atrophy diagnosed as atrophic connective tissue panniculitis is presented. Reconstruction of both cheeks was performed with two staged latissimus dorsi muscle flaps. The initial good result on the right cheek deteriorated as the disease continued to progress after surgery. The good result on the left cheek, however, remained stable. Detailed clinical examinations, laboratory analysis, and deep biopsies from the affected areas are important for accurate diagnosis. Reconstructive procedures should be delayed while the disease is still active. 相似文献
Recently new operations have been defined for soft sets. In this paper, we study some important properties associated with these new operations. A collection of all soft sets with respect to new operations give rise to four idempotent monoids. Then with the help of these monoids we can study semiring (hemiring) structures of soft sets. Some of these semirings (hemirings) are actually lattices. Finally, we show that soft sets with a fixed set of parameters are MV algebras and BCK algebras. 相似文献
Nanocomposites based on an amorphous copolyester (PCTG) were obtained by melt mixing, changing the screw speed and the nature of the surfactant, which differed in polarity and molecular volume. Using Young's modulus as a measure of the dispersion level, a less‐polar nature and a higher molecular volume of the surfactant appeared as positive structural factors for dispersion of the clay in the less‐polar PCTG. The Cloisite 20A, which led to the highest modulus (widest dispersion), was mixed at different contents with PCTG at the observed optimum screw speed (200 rpm). Intercalated structures were observed by WAXD and TEM. The dispersion was wide, as observed by TEM, and led to a large (77%) modulus increase after 7% organoclay addition and to important increases in both tensile yield stress and dimensional stability in creep.
Swirling fluidized bed (SFB) is a newer version of the well-known bubbling bed and very little know. An insight study is therefore required for complete understanding of the hydrodynamics of a SFB operation. The current study was conducted on stable regime of a SFB operated at different blade fin angles, blade inclination angles, particle densities and superficial air velocities. Roughly one quarter of the fluidized bed was photographed and its velocity vector field plots were generated using a MATLAB supported particle tracking velocimetry (PTV) technique. At lower superficial velocities, Gaussian distribution of the velocity vectors was predicted along the radius of the bed. Particles in the vicinity of the bed walls moved relatively slower than those marching in the middle of the bed. However, at higher superficial velocities, the particles closer to the cone boundary were moving with velocities comparable to the particles in the middle of the bed. Unlikely, the particles closer to the outer bed wall kept on moving with lower velocities regardless of increasing superficial air velocity. A further look into individual velocity vector profiles revealed negligible influence of smaller blade angles (9° and 12°) on particles’ motion. The overall velocity magnitude decreased by 6% with 3° increase in blade fin angle and by 9% with 5° increase in inclination angle. Contrarily, the particle velocity underwent a monotonic decrease with particle density. 相似文献
ABSTRACTConjugated polymer/graphite nanocomposites have been known as high performance materials owing to improve the physicochemical properties relative to conventional once. Multilayered polymer nanocomposites based on polypyrrole (PPy), polyvinylchloride (PVC) as matrices and p-phenylene diamine (PDA) as linker were prepared via chemical in situ polymerization process and subsequently investigated the physical characteristics of fabricated nanocomposites at various loadings. The structural characterization and morphology of prepared nanocomposites were inspected by Fourier transform infrared spectroscopy (FTIR), X-ray photon spectroscopy (XPS), energy dispersive X-ray spectroscope (EDX), field emission scanning electron microscope (FESEM), respectively. The composite III showed higher thermal stability at 10 wt% loading of PPy. According to differential scanning calorimetry (DSC), the glass transition temperature (Tg), melting temperature Tm, and crystallization temperature (Tc) of nanocomposites increases with PPy loading (2–10 wt%) owing to crosslinking and chain rigidity. Moreover, higher surface area was displayed by the multilayered PPy/PVC/PDA@FG nanocomposites. Remarkably, electrical conductivity of ultimate nanocomposites was also found to be a function of PPy loading. 相似文献