Research On Preparation Of Calcium Sulfate Whisker

At present, it is a new international developing tendency for Materials Science to add whisker into resin, metal and ceramic matrix to prepare high-performance composite materials. However, the high price of traditional fabrics, such as carbon fabrics, silicon carbide fabrics, silicon nitride fabrics, severely restrit the civil nature of composite materials, thus developing cheap fabrics in composite materials become one of the hot issues. As a new material, the calcium sulfate whisker has the merit of similarity mechanical properties to carbon fiber, high temperature resistance, good compatibility and smoothness, regeneration performance, low toxicity, easiness for surface treatment,and so on. while its price is 1/200~1/300 of carbon fiber.Because of its high performance price ratio and the tremendous application prospect in civilian material , so it becomes the focus of research in the area of materials. Presently, the main preparation methed of calcium sulfate whisker is he hydrothermal method, however which requires high temperature and pressure. The low length-diameter ratio, high energy consumption,high requirements on the reactor, and difficult to production on large scal, ristrict the methed on the industrial application.According to this problem, use of industrial products, ammonium sulfate and calcium chloride as raw material, propose two new techniques of calcium sulfate whisker synthesis:(1) Liquid Phase Synthesis of new process, use the organic liquid catalyst MZ-1 which exploit by myself, at room temperature, the length of between 70 to 80, diameter 0.5 to 1.0, length-diameter ratio of 80 of dehydrate calcium sulfate whisker were prepared and well dispersed;(2) Low Temperature (0 ~ 100℃) Hydrothermal methed ,between 80 to 90 in length, diameter of between 0.5 to 1.0, length-diameter ratio of 85 of calcium sulfate dehydrate the whiskers were prepared, the process greatly enhanced the response of raw materials concentration.The results show that, the liquid phase catalytic synthesis of optimal conditions: the reaction concentration 0.5mol/L, organic liquid catalyst MZ-1 dosage of 50ml, pH value controlled at 3, ultrasonic time of about 30min. Low temperature(0~100℃)hydrothermal methed of optimal conditions: raw material concentration 1.0mol/L, reaction temperature 80℃, reaction time of 30min, stirring speed 120r/min.Also explores the study of dihydrate calcium sulfate whisker be converted to hemihydrate calcium sulfate whisker and anhydrous calcium sulfate whisker at a high temperature, get the great length-diameter ratio of hemihydrate or anhydrous calcium sulfate whisker.