MELT VISCOSITY OF CALCIUM-CARBONATE-FILLED LOW-DENSITY POLYETHYLENE -INFLUENCE OF MATRIX-FILLER AND PARTICLE-PARTICLE INTERACTIONS

The melt viscosity of filled polymers depends on the filler particle p acking. It is shown that the maximum particle packing for a low densit y polyethylene, filled with calcium carbonate, depends strongly on the filler surface treatment. This packing can be evaluated from melt vis cosity measurements using the Quemada model. From contact angle measur ements and using the Lee unified adhesion theory, it has been demonstr ated that the maximum packing depends on particle-particle and matrix- filler interactions. The competition between both types of interaction leads to different organizations of particles in the composite.