2. Influence of operating conditions in the internal mixer

To study the effect of mixing process parameters on clay dispersion, it is convenient to start with an internal mixer, in which flow conditions can be more easily controlled than in a twin-screw extruder. In the following, the formulation chosen is 85/10/5 by mass, with homopolymer PP as matrix, PP-g-MA with a maleic anhydride content of 3.1% by mass as compatibilizer and Cloisite ^© C20 as OMMT. The matrix (PP + PP-g-MA) is first melted at 50 rpm for 2 min, then the OMMT is introduced and mixed at various rotor speeds and mixing times. Samples are then characterized in terms of area ratio [equation (2) ] and apparent...