| Mixing studies of glass fibers and silica filler into thermoplastics, two polypropylenes and polyamide 12, in co-rotating twin screw extruder were carried out. Fiber length and agglomerate sizes were determined at various positions along the screw in the twin screw extruder.;The damage of glass fibers at various conditions was investigated by varying viscosity, screw speed, screw configuration and glass fiber length and diameter. Increasing screw speed, melt matrix viscosity and glass fiber concentration were found to increase the extent of fiber breakage. Based on our experimental data and Euler buckling theory the composite modular kinetic model to describe glass fiber damage was developed. Regions of major and minor fiber breakage in co-rotating twin screw extruder were established. The simulation program based on experimental data and kinetic constants was developed. Comparisons were made between simulated results and experimental data.;Silica agglomerates were characterized by measuring their mass average values to avoid subjective result due to small filler particles. Silica agglomerate sizes as effected by viscosity, screw speed and filler concentration in co-rotating twin screw extruder were studied. The composite modular kinetic model for evaluating silica agglomerate breakup was developed. The kinetic constants of breakup and re-agglomeration for various conditions were calculated based on the stresses applied to agglomerates and their cohesive strength. Experimental data were compared with calculated results.;Generally, calculated results from the modified kinetic model of glass fiber and silica filler breakup showed reasonable agreement with experimental data. |
