In the present research , the rheological and the diffusion properties of polymer melt composed of (polypropylene- polymethylmethacrylate ) unfilled_ filled with different amounts of Iraqi bentonite powder (4,8,12 and 16) wt% were studied. Single screw extruder was used for development of these blends .The rheological behaviour of these blends was investigated by using rotational concentric type rheometer .
The rheological properties shear rate( ( , apparent viscosity (a) and shear stress (τ) , at various temperatures ( 240 ˚C, 250˚C and 270 ˚C) were studied and found to be increase with increasing the amount of filler and decrease with increasing temperature. The flow curves were determined in the range of shear rate from about (2.625*10 2 to 4.70*10 2 ) s-1. The activation energy was also calculated, the values of activation energy varied from (102.2148 to 131.2206) KJ/Mole for different formation.
Absorption test was carried out in Glycerin at different immersion time. The diffusion coefficient (D) values ranged (1.54*10-8 to 2.48*10-3) cm2/sec for immersed in Glycerin.
The diffusion test also was carried out at different temperatures in order to show the effect of temperature on diffusion coefficient. It was found that the diffusion coefficient values increase with increasing temperature. All these samples are obeyed Fickian behavior and the activation energy (E) increases with increasing amounts of Iraqi bentonite powder (4,8,12 and 16) wt%.