ABSTRACT:To investigate the effect of a flame retardant on PC/ABS alloy systems, a reactive-type brominated epoxy resin was used as a flame retardant, and mixed with PC/ABS at various amount using a twin-screw extruder. The rheological, morphological, mechanical, and thermal properties were investigated as a function of acrylonitrile (AN) content in ABS. The shear viscosity of the PC/ABS blend increased as the AN content in ABS increased. Temperature drastically affected the shear viscosity in the ABS matrix, but not as much in the PC matrix. A blend of PC 50% containing AN 22% is suitable to process because its shear viscosity is low in the high shear rate region and its mechanical properties drastically increase in the beginning of the PC matrix. In addition, gradual increases of heat distortion temperature were observed in the entire range of the PC content.

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Aspects of thermal, morphological, and rheological properties of biodegradable poly-D(-)(3-hydroxybutyrate) (PHB) blended with poldethylene oxide) (PEO) have been studied. Thermal properties and morphology of the blends were examined by scanning electron microscopy and differential scanning calorimetry, respectively. A rotational rheometer with parallel plate geometry was also adopted to investigate the rheological properties of these blends. In addition, dynamic viscoelasticity was measured by a Rheovibron as functions of time and temperature. From these measurements, PHB and PEO were observed to be miscible in the melt state. In the case of the blend system 80/20 PHB/PEO by weight, the vacant domains of the PHB were filled with PEO particles, and this morphological state enhanced the rheological properties. Furthermore, PHB and its blends were found to have high crystallinities, but to have unstable thermal behavior about T , .

Ga 2 O 3 based gas sensors have limited use at a temperature lower than 400 C because of their poor performances at low temperatures. Efforts to further improve their performances at room temperature are necessary. This study examines the sensing properties of surface-nitridated Ga 2 O 3 nanowires toward CO gas. Surface-nitridated Ga 2 O 3 nanowires were fabricated by thermal evaporation of GaN powders followed by thermal nitridation in an NH 3 atmosphere. Scanning electron microscopy and transmission electron microscopy showed that the GaN shell layer in a typical surface-nitridated nanowire had a thickness of $21 nm and excellent shell layer thickness uniformity. Multiple networked surface-nitridated Ga 2 O 3 nanowire sensors showed responses of 160-363% to CO concentrations of 10-200 ppm at 150 C. These responses were 1.6-3.1 fold stronger than those of pristine Ga 2 O 3 nanowire sensors at the same CO concentrations and stronger than those of many pristine metal oxide nanostructures and Ga 2 O 3 /metal oxide core-shell nanowires at similar temperatures. The results showed that the sensitivity of Ga 2 O 3 nanowires could be enhanced by simple ammoniation treatment. The enhanced response of the surface-nitridated Ga 2 O 3 nanowires to CO gas can be explained based on a potential barrier carrier transport mechanism combined with a surface depletion mechanism and excellent shell layer uniformity. Fig. 1 (a) SEM image and (b) XRD pattern of surface-nitridated Ga 2 O 3 nanowires.This journal is

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