Research On Preparation And Properties Of PP/modified Kaolin Composite Material

Hard kaolin is a kind of mineral resources in our country, it distributes a wide range of areas, it is abundant, up to tens of billions of tons. Kaolin has high kaolinite, it is unique in China, and it also has high value of deposit. Hard kaolin has little other kinds of mineral, but the kaolinite is more than90%, the defect is carbon, iron, titanium and other mineral more staining. Hard kaolinite has deeper color than other kinds of kaolin, the general color is light gray, black, brown and natural low whiteness. If it is not processed meticulous, the natural whiteness and refined white degree is not high, which limits its application in all aspects of the development and has very low utilization. Therefore, reduce the iron content of kaolinite and whitening is a key link of processing and utilization of hard kaolin. The use of Polypropylene (PP) is second only to polyethylene (PE), but it has shortcomings like the molding shrinkage rate, flammable and low temperature brittleness. Modified hard kaolin has stable chemical properties, high cover rate, high whiteness, good insulation and excellent performance of amorphous structured if it is used in PP as filler, thus can improve the performance of the polymer. So the research of how to combine PP and modified hard kaolin has very widely value. This article had studied the preparation of modified hard kaolin and its application in PP, the results showed that the properties of the composites was enhanced, and it added the value of the modified hard kaolin.We used hard kaolin from Zibo as raw materials, on the base of the analysis of the mineral composition and chemical composition, studied the effects of the feed size, calcining temperature,holding time, additive dosage and ball diameter on whiteness of kaolin, discussed the whitening mechanism of the additives, the analysis of structure and properties of the calcined products. The experiment adopted two different fine processing, to determine the optimum process parameters of hard kaolin calcining. We used stearic acid, silane coupling agent, titanate coupling agent of aluminum to modify the calcined kaolin, compared and analyzed the experimental results. The results showed that the stearic acid on the surface of kaolinite powder modified activation was strong, but the polymer substrate binding effect was not good; the silane coupling agent on the surface of kaolinite powder modified activated with stearic acid was slightly worse, but the comprehensive results and polymer effect than stearic acid was good, and it had a high cost; aluminum titanate coupling agent had not only a higher effect to the kaolin surface modification of powder activated degrees stronger and polymer, and it had low cost.We made the PP/modified kaolin composite through blending, extrusion, granulation, injection molding the different modified hard kaolin and PP. And used XRD, SEM, electronic universal testing machine, horizontal and vertical burning tester, limiting oxygen index determination test methods and so on to composite the structure, interface morphology, mechanical properties, and flame retardant properties. The results showed that the aluminum titanate coupling agent modified calcined kaolin was uniformly dispersed in PP, the flame retardatory and mechanical properties were obviously improved.The experimental studied on the calcined kaolin intercalated modified, moisture absorption properties by using potassium acetate of the calcined kaolin physical grinding to produce super fine lamellar materials. Through the XRD and infrared testing that could be seen, the lamellar structure of kaolin potassium acetate could be entered to stretch its spacing, and the kaolinite layers of space was expanded. The intercalation of the modified kaolin by surface modification, blending with polypropylene, extrusion, granulation,injection molding, testing its effect, as could be seen, based on the same additives, PP/intercalated in the mechanical and flame retardant properties than PP/modified kaolin increased slightly modified kaolin composite.