Rice Husk Ash (RHA)-Based Silica as Filler in Polypropylene Composite: Effect of Peroxide-Containing Silane on the Rheological Behavior

Abstract

The effect of incorporating silica filler derived from rice husk ash (RHA) on the rheological properties of polypropylene was studied using a Brabender slit capillary die. The melt shear stress and viscosity increased with filler content. The filler was treated with a silane-based coupling agent. The silane used was Prosil 2020, a proprietary silane coupling agent containing the peroxide bis(t-butyl peroxy)di-isopropyl benzene. The peroxide induces βscission of the polypropylene molecular chains reducing the shear stress and viscosity. Hence the filler and the coupling agent (peroxide concentration) have opposing effect on the rheology of the composite's melt. For high filler content melt, the peroxide effect is more prominent, lowering the overall stress and viscosity. At higher shear rate, the effect of filler concentration is more dominant. Mixing torque and melt flow index studies support the rheology measurements by the slit die technique.

Tensile properties, swelling, and water absorption behavior of rice‐husk‐powder‐filled polypropylene/(recycled acrylonitrile‐butadiene rubber) composites

“…Although a large number of published papers exists on PP/RH composites [7–14], and the use of white rice husk ash (WRHA) and black rice husk ash (BRHA) in plastics [15–29], there was no work reported on the use of recycled acrylonitrile‐butadiene rubber (NBRr) in PP in the presence of RHP filler. The objective of this work was to explore the mechanical properties, swelling behavior, and water absorption capacity of PP/NBRr/RHP composites.…”

Foam extrusion of polypropylene–rice husk composites using CO2 as the blowing agent

“…3 However, before 21st century, most of the research focused on using incinerated rice husk ash as a reinforcement for composites, since rice husk ash contains about 95% silica and it possesses superior mechanical properties than a polymer matrix. 4–11 Yang et al. compared the physical properties of composites made of wood flour and rice husks and found that although the mechanical properties of rice husks are poor than those of wood flours, 12 polypropylene (PP)/rice husk composites possess better thermal stability than PP/wood flours composites owing to the presence of silica in rice husk.…”