Acid treated halloysite nanotubes reinforced PP/ABS blends and its composites: Influence on mechanical and thermal properties

Abstract

Halloysite nanotube (HNTs) is treated with sulphuric acid (H2SO4) which results in the formation of amorphous silica over the HNTs surface. The acid-treated HNTs and untreated HNTs are reinforced in a ratio of 80:20 (wt/wt) of polypropylene (PP) to acrylonitrile butadiene styrene (ABS) blends using melt extrusion. The dual compatibilizers of grafted maleic anhydride monomer over polypropylene and styrene ethylene butadiene styrene are used as compatibilizers for compatibilizing HNTs filled blend and its composites. The cryofractured and etched HTNs filled blends and its composites reveal the development of droplet embedded in the matrix. A significant decrease in average droplet diameter is observed with the incorporation of acid-treated HNTs and untreated HNTs filled blends and its composites. Acid-treated HNTs and pure HNTs filled blends and its composites influence the crystallinity of the PP phase as compared to pure blends. In addition, it has influenced thermal stability. The refined morphology and compatibilization improves the tensile and impact properties of untreated HNTs and acid-treated HNTs filled blends and its composites in comparison to pure blend. Tensile fractured scanning electron microscope (SEM) image shows the formation of fibrils. Whereas the impact fractured SEM image shows the resistance to dislodge the ABS droplets. Acid-treated HNTs filled blends and its composites show the highest tensile and impact properties with ∼37% increase in tensile modulus and ∼49% increase in impact strength in comparison to pure blends.