Papers by Keyword: T-ZnOw

Abstract: Surface hydrophobic modification of T-ZnOw was experimented with silane coupling agent KH-570(gamma-(methylpropyl acyloxy)trimethoxysilane). It was shown by FT-IR that the whiskers was modified by silane coupling agents molecular compounded with the Zn-OH of whiskers. The effect of grafted modification with KH570 on hydrophobicity of T-ZnOw was characterized with dispersion stability test in an organic solvent and measuring the contact angle between the whiskers on distilled water. The results showed that surface treatment of T-ZnOw with KH570 improves hydrophobicity of whiskers simultaneously, and the modified whiskers have much slower settling rates than the pristine whiskers in the liquid paraffin. The contact angle between the modified whiskers with distilled water is 137.75 degrees, which is a significant increase.

Abstract: The 0-3 and 1-3 composites have been widely used to produce various kinds of piezoelectric devices. This article focuses on the damping properties of the epoxy/piezoelectric composites. Due to the piezoelectric effect, the composites are expected to improve the damping properties and can be used in the field of vibration reduction and noise control. Two piezoelectric materials were embedded into the epoxy resin to make specimens, T-ZnOw/epoxy resin as 0-3 and PZT fibers/epoxy resin as 1-3 composite. With the method of dynamic mechanical analysis, the temperature dependence of the mechanical storage modulus and the loss factor (tanδ) were measured at different frequencies. The experimental results clearly show that the loss factor increases when testing frequency is higher. In this study, the piezoelectric damping and the viscoelastic effect are discussed and both of them contribute to the damping property of the composite system.

Abstract: Tetra-needle like zinc oxide whiskers (T-ZnOw) were doped with Al3+, Fe3+ or Ag+. The morphological structures and the doped ions were characterized, and the results indicated that mostof the Aluminum existed in a second phase of ZnAl2O4, most of the Fe3+ solid-solutioned into the crystal lattice and the silver generated as nano-particles on the surface of the needles of the ZnO whiskers. Anti-bacterial experiments gave the result that Fe3+ doped T-ZnOw and the nano-silver adnascent ZnOw had obvious effect of killing and inhibiting the bacteria such as Staphylococcus Aureus (ATCC 6538), Escherichia Coli (ATCC 25922) and Candida Albicans (ATCC 10231). The minimum inhibitory concentrations (MIC) of the related doping T-ZnOw were 55~440 PPM. Further experiments indicated that there appeared high margin of safety and no stimulation on skins or eyes for the tested animals. Products such as plastics, coatings, fibbers and papers containing 2wt% of the doped T-ZnOw had more than 99% efficiency for anti the mentioned bacteria. Effect of degradation of organic compound for the doped T-ZnOw was also evaluated by degradation of formaldehyde. The mechanism was tentatively put forward to explain the phenomena and the effect of antibiosis.