HIGH ORIENTATION OF TOUGHENED CHALK-FILLED ISOTACTIC POLYPROPYLENE - PREPARATION AND PROPERTIES

Chalk-filled isotactic polypropylene (iPP) toughened by modifying the interfaces with liquid oligomer of ethylene oxide was subjected to high deformation at elevated temperature. Oriented chalk-filled material exhibits interesting properties: high concentration of open interconnected pores, high elastic modulus, high tensile strength, ability to absorb large quantities of liquids, white color and roughness of the surface. A continuous process for the production of oriented, toughened, chalk-filled isotactic polypropylene is described. The stretching ratios which can be achieved range from 4 to 8 for modified chalk concentrations with compositions of 60 and 40 wt%, respectively. Solid state extruded, toughened, chalk-filled iPP prepared for comparison exhibits similar morphology and properties as drawn toughened chalk-filled iPP although it contains much less voids.