EFFECT OF PARTICLE SIZE OF CALCIUM CARBONATE ON POLYPROPYLENE COMPOSITES

Abstract

A polymer is rarely used as a pure material and the baseline physical, chemical and rheological properties such as molecular weight, strength, stiffness and viscosity are often modified by the addition by the fillers or by blending with another polymer. However, as many polymers are immiscible compatiblisation and graft processing polymer blends are very important technique to increase miscibility of the blends as well as improve to chemical, physical and mechanical properties. Reactive extrusion or melt processing is one of the most appropriate techniques for improving polymer properties. Compatiblisation and graft polymer processing are often carried out under reactive extrusion conditions. This technique is an efficient approach because it is easy, inexpensive and short processing time. Although reactive extrusion has numerous advantages one of the limitations is degradation of the polymer under the high temperatures and mechanical stresses encountered. In the polymer industry , because of increasing customer demand for improved product quality ,optimizing the polymerization process by decreasing product costs and controlling the reactions during the polymerization has become more important. It can be said that any method used for monitoring the polymerization process has to be fast, accurate and reliable Both online and inline process may be involved in in process monitoring. The primary information from in- process monitoring is used for identifying and understanding molecular structure and changes, optimizing and improving process modeling and understanding whether the process is under control. This also involves considering whether the products have the required properties.

Talc filled polypropylene composites are designed to improve the properties and to lower the overall cost of engineering plastics. In this study the effects of adding talc with variable particle size on the mechanical and thermal properties of polypropylene was investigated. A composite of Polypropylene with constant concentrations (24%weights) of talc was prepared on twin screw extruder (Co-rotating). The composite showed improved mechanical as well as thermal properties on addition of different size of filler. It is also observed that mechanical properties as well as thermal properties increase with decrease in particle size.