Effect of heat treatment on the microstructure and properties of CVD SiC fiber

In this study, the effect of heat treatment on the room temperature strength of W-core Si C fiber produced by chemical vapor deposition（CVD） was investigated. Thermal exposure in the temperature range of 900–1000？C decreases the strength of the Si C fiber. Fracture morphology analysis indicates that failure initiations predominantly take place at the W-core/Si C interface. A reaction layer that formed at the W-core/Si C interface during thermal exposure degraded the fiber strength and an empirical linear relationship of strength vs thickness of the reaction layer can be obtained. The kinetics of the growth of the W-core/Si C reaction layer were determined.

Effect of chemical treatment of silicon gel on tissue compatibility

Background Silicon gel is unfavourable for cell attachment and growth. This study was to study if pretreating the surface of silicon gel with chemical agents affects the proliferation of epithelial cells Methods Silicon gel was made and treated with either mixed acid solution (containing 232 g/dm 3 of H 2SO 4 and 8 g/dm 3 of K 2Cr 2O 7) or 300 cm 3/dm 3 peroxide for 5, 10, and 15 minutes or 10, 15, and 20 minutes, respectively The cultured corneal epithelial cells were seeded onto those silicon gels and kept for 13 days Immunohistochemical investigations were then carried out for integrin (alpha 6 or beta 4) and actin KH*2/5DResults Growth of the epithelial cells in silicon gels treated with mixed acid solution for 10 minutes and 15 minutes was much significant than that in the untreated gels After a 12-hour culture, a small number of corneal epithelial cells were proliferated on the surface of the silicon gels that had been treated with peroxide for 15 minutes After a 3-day culture, those cells were further proliferated and fused together The corneal epithelial cells did not grow well in the silicon gels treated with peroxide for 10 or 20 minutes Immunostaining revealed the expression of actin and integrin alpha 6 or beta 4 on the silicon gels that were treated with mixed acid solution for 10 minutes or peroxide for 15 minutes Conclusion Silicon gels treated either with mixed acid solution for 10 or 15 minutes or with peroxide for 15 minutes improves cell proliferation

Surface Modification of Poly-(p-Phenylene Terephthalamide) Pulp with a Silane Containing Isocyanate Group for Silicone Composites Reinforcement

A silane containing isocynate groups（3-（trimethoxysilyl） propyl cyanic acid ester,NCO） associated with hexamethyldisilazane（HDMS） is used to modify the surface of poly-（p-phenylene terephthalamide）（PPTA） pulps. As concerns surface chemistry,Attenuated Total Reflection Flourier Transformed Infrared Spectroscopy（ATR FT-IR） and X-ray photoelectron spectroscopy（XPS） confirm that NCO associated with HDMS silylated PPTA pulp surface successfully. While the modified PPTA pulps are used as reinforcing fillers for silicone composites,the dispersibility and storage stability of the composites are improved as Mooney testing indicated. The silicone composites filled with modified PPTA pulps present a higher tensile strength and much higher broken elongation（3.30 MPa and 166.54%） than that with unmodified pulps（3.08 MPa and 68.47%）,respectively.