Fabrication of Al2O3/ZnO and Al2O3/Cu Reinforced Silicone Rubber Composite Pads for Thermal Interface Materials

Thermal interface materials (also known as thermal pads) are widely used as a crucial part to dissipate heat generated in miniaturized and integrated electronic components. Here, we systematically investigated the effects of small ceramic and metallic powders in rubbery thermal composite pads with a high content of aluminum oxide filler on the thermal conductivity of the composite pads. We optimized the compositions of aluminum oxide fillers with two different sizes in a polydimethylsiloxane (PDMS) matrix for rubbery composite pads with a high thermal conductivity. Based on the optimized compositions, zinc oxide powder or copper powder with an average size of 1 μm was used to replace 5 μm-sized aluminum oxide filler to examine the effects of the small ceramic and metallic powders, respectively, on the thermal conductivity of the composite pads. When zinc oxide powder was used as the replacement, the thermal conductivity of the rubbery composite pads decreased because more air bubbles were generated during the processing of the mixed paste with increased viscosity. On the other hand, when the copper powder was used as a replacement, a thermal conductivity of up to 2.466 W/m·K was achieved for the rubbery composite pads by optimizing the mixing composition. SEM images and EDS mapping confirmed that all fillers were evenly distributed in the rubbery composite pads.

Surface Topology of Zinc Oxide Powder Prepared by High Temperature Sol Gel Combustion Method

ZnO is most widely and most attractive element in today’s research. ZnO powder is not available naturally. The ZnO powder was prepared by different methods. Here in this paper the preparation of powder was discussed. The powder was prepared by high temperature sol gel combustion method. Here in this study selected temperature was 500 0C ± 10 0C. to form the pure ZnO powder the synthesized powder was sintered at 6500C ± 10 0C. After sintering the white ZnO powder was formed with amorous in nature.This method was easy and high yield. The powder was characterized by using XRD and SEM. From XRD grain size was calculated. Using SEM the particle size, specific surface area, surface roughness and the surface morphology was studied.

A Study on Sebum Hardening Effect of ZnO Powder

Zinc oxide is transparent inorganic UV absorber and widely used as a sunscreen. But sunscreen on the skin is easily erased by sebum, so zinc oxide with a sebum curing function was studied. In this study, a zinc oxide powder was prepared using zinc chloride and sodium hydroxide via a hydrothermal synthesis method. The process conditions including reaction temperature and sodium hydroxide ratio were determined. Particle size was determined using XRD and SEM, and process tendencies were checked using the gelling test method. When the sodium hydroxide ratio was lower than 58.7 wt%, the gelling time was reduced, and when the temperature was lower than 60 ^o, the gelling time decreased. ZnO and Simonkolleite confirmed that the gelling time was reduced when the mixture comes out.

A Facile Method for Preparing a Superhydrophobic Block with Rapid Reparability

Superhydrophobic surfaces are fragile and are prone to failure in harsh outdoor environments. The preparation of robust superhydrophobic surfaces with stable performance and excellent properties can extend their application. In this paper, we report a simple and cost-effective method to prepare a superhydrophobic block using superhydrophobic zinc oxide powder and die pressing. The prepared sample has a contact angle of 163° and a sliding angle of 7°. Tests show that the superhydrophobic block can resist the impact of water flow, maintain its superhydrophobicity after friction or knife scraping, and quickly repair the destroyed surface by sandpaper abrasion. The sample exhibited excellent self-cleaning effect, robust mechanical property, and rapid repairability. This preparation method is also environmental-friendly and easy to operate. It will have a wide application prospect in many important fields.

Sitotoksisitas Kombinasi Seng-oksida dan Ekstrak Curcuma longa Terhadap Fibroblas Gingiva Manusia

The use of zinc oxide - eugenol as periodontal dressing is controversial due to the toxic nature of eugenol and Curcuma longa Linn as a safe natural herbal, is expected to replace eugenol function. Previous research has proven that the combination of zinc oxide with Curcuma liquid extract has an antibacterial properties and the use of those as wound dressing through in vivo studies proved to accelerate wound healing. The ingredients applied to the oral cavity must benon-toxic and biocompatible, therefore cytotoxicity testing 1 is required. To determine the cytotoxicity of zinc oxide and Curcuma longa extract combination on human gingival fibroblast cells. Cytotoxicity test of combination of zinc oxide powder with Curcuma liquid extract was done at ratio of 1: 1 (group A) and 2: 1 (group B), Curcuma liquid extract (group C) and zinc oxide powder (group D), which performed on human gingival fibroblast culture-cells (3-5x103 densities) in 96 wells microplate. MTT essay was used to analyzed with IC50 parameters. Statistical analysis using oneway Anova and LSD. The number of living cells in group A = 64.819%, group B = 59.452%, group C = 52.859% and group D = 60.502%. There was no significant difference between the groups of A, B, D but those groups were significantly different to group C. Combination of zinc oxide with Curcuma extract ratio of 1: 1 and 2: 1, zinc oxide powder and Curcuma liquid extract are not toxic to human gingival fibroblast at IC50.