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As an important engineering material, polycarbonate (PC) has been used widely. When exposed to the environment, PC will have aging process, which will reduce its performance and efficiency. This article studies the changing regularities of PCs structure and properties of ageing in western areas of China by measuring the change of intrinsic viscosity (IV), thermal decomposition temperature, glass transition temperature, and the groups within PC. The analysis of its IV, DSC, and thermo gravimetric analysis exhibited the same changing regularity, i.e., the aged PC (in Lasa, Yuli, and Jiangjin) experienced degradation and crosslinking, while degradation occurred earlier in the process of ageing, crosslinking predominated in later period. In addition, the results of UV absorption spectra and infrared absorption spectra showed the evidence of decomposition of the ester groups, resulting in the production of alcohol and phenol. And the results of mechanical tests indicated that the ductility disappeared mainly in the first year of outdoor aging. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The properties and structure of Bisphenol A polycarbonate (PC) under hydrothermal aging were investigated. The results of mechanical testing indicate that there is obvious elongation at break on the curve of PC samples before hydrothermal aging and no elongation at break after aging. After aging, the bending strength and the tensile strength of PC increase. According to scanning electron microscopy photographs of fracture surfaces, after hydrothermal aging, there are many fragments linked to the fracture surface and the length of deformation at break disappears. Differential scanning calorimetry analysis shows that the glass transition temperature ( T g ) of polycarbonate increases after hydrothermal aging. Fourier transform infrared spectroscopy shows hydrolytic degradation after hydrothermal aging.

This article describes the exploration of operating parameters collection and analysis system for the marine diesel engine based on AC6111 high speed A / D acquisition card. Pressure sensor is used for the engine cylinder pressure signal creation. After amplified and filtered, the signal is sent to the marine diesel engine parameters acquisition and analysis procedures which compiled by Visual Basic language to collect the cylinder pressure and save the pressure data in real-time. Meanwhile the cylinder pressure curve, transient speed curves and heat release curve adapting to the change of crank angle are displayed. At the same time, the coordinate of the operating parameter can be showed on the curves; we can also check the engine performance through the playback function.

A new generation of MgCl2-supported catalysts for the polymerization of propene without any external donors was prepared. Two diethers, 9,9-bis(methoxymethyl)fluorene (for Cat-A) and 2,2-dipropyl-1,3-dimethoxypropane (for Cat-B) differing in the bulkiness of alkyl substituents in position 2, have been used as internal donors in MgCl2/TiCl4/diether-AlR3 catalysts. The weight-average molecular weights produced with both catalysts were over 3.5×105 at low temperature in slurry polymerization (