Polypropylene/organically modified-grafted mica/organoclay hybrid nanocomposites: Preparation, characterization, and mechanical properties

Polypropylene (PP) was reinforced using both an organically modified-grafted mica (OMGM) and an organically modified montmorillonite (OMMT) as debonding rigid nanoparticles to improve its impact resistance with the advantage of increasing its Young's modulus and crack growth resistance. For this purpose, mica was organically modified using diacetone acrylamide, a double bond-ended modifier. To improve further the polymer/nanoparticle interfacial interactions and delamination of layered particles, PP graft maleic anhydride was grafted on the modified mica. Various amounts of OMMT, 0-3 wt% along with 1 wt% OMGM were used to reinforce the PP matrix. The effect of OMMT content on the crystallinity degree, fracture morphology and mechanical properties of resultant hybrid nanocomposites was investigated. The results showed that the incorporation of 1 wt% OMGM and 0.5 wt% OMMT resulted in the highest impact resistance (68%) and fracture toughness (5.7%) when compared with neat PP. In addition, the elastic modulus and yield stress were increased 12 and 14.5%, respectively. Transmission electron microscopy exhibited a fairly good dispersion of smaller OMMT and longer OMGM tactoids in the resultant hybrid nanocomposite. A slower crack growth rate was observed for the hybrid nanocomposite because of the barrier property of the silicate layers against the crack propagation when compared with the neat PP. However, increasing of the OMMT content caused the nanoparticle agglomeration and lowering the impact resistance in the resultant hybrid nanocomposites. POLYM. COMPOS., 40:1718-1730, 2019. (c) 2018 Society of Plastics Engineers