Insulating materials for electronic packaging should ideally have high strength and thermal conductivity . Ceramic/polymer composite is one of the candidates for such materials. In this work, Al 2 O 3 /epoxy composites with very high flexural strength and thermal conductivity were prepared using a new processing technique consisting of the gelcasting, sintering and vacuum infiltration methods. Al 2 O 3 green bodies were first formed by gelcasting. After being degreased at 600 °C, the green bodies were sintered at different temperatures from 1200 °C to 1500 °C, and porous Al 2 O 3 ceramic skeletons with different porosity were resulted. The porosity was readily controlled by the sintering temperature . Higher sintering temperature resulted in lower porosity and larger average grain size in the Al 2 O 3 ceramic skeletons. Epoxy was vacuum infiltrated into the sintered porous Al 2 O 3 ceramic skeletons to form Al 2 O 3 /epoxy composites by curing. High Al 2 O 3 loadings up to 70 vol.% in the composites were achieved. The flexural strength and thermal conductivity of the Al 2 O 3 /epoxy composites were found to reach 305 MPa and 13.46 W m −1 K −1 , respectively. These results are remarkably higher than those previously reported in the literature. This work provides an effective approach for fabricating high performance ceramic/polymer composites for electronic packaging.
Du Qi,Fang Chuangdong,Qi He,Benjakul Soottawat,Aubourg Santiago P.,Zhang Bin
Phosphates and trehalose are widely accepted additives in animal muscle products. In this study, the effects of pre-soaking with sodium tripolyphosphate (STPP) and trehalose under vacuum permeation (VP) conditions on the physicochemical properties of shrimp muscle were evaluated over 120 d of frozen storage. The results indicate the STPP/trehalose-VP treatments significantly reduced the thawing loss and prevented changes in the texture, myofibrillar protein (MP) content, and Ca2+-ATPase activity of shrimp muscle during frozen storage compared with results of control and individual STPP or trehalose soaking treatments. The histological structure analysis revealed the permeated STPP/trehalose distinctly inhibited the dissociation of muscle fibers and reduced physical damage to connective tissues during storage. Furthermore, analysis of the thermal properties indicated STPP/trehalose treatment increased the Tg’ values of shrimp muscle tissues, likely by restricting the mobility of water molecules in muscle tissues and embedding proteins in the glassy matrix. Thus, the physical destruction caused by ice crystal growth was greatly reduced, due to the absence of water molecules around muscle proteins during frozen storage. Accordingly, the combined STPP/trehalose-VP treatment significantly enhanced the stability of frozen shrimp, and the results support the application of traditional cryoprotective additives. The treated shrimp can be stored at comparatively higher temperatures with limited physicochemical reactions during frozen storage.
危险品化学品经营许可证（带存储）