Matrix tacticity controlled tuning of microstructure, constitutive behavior and rheological percolation effect of melt-mixed amino-functionalized MWCNT/PP nanocomposites

Amino-functionalized multi walled nanotube (MWCNT-NH2) filled isotactic PP and isotactic-syndiotactic (70:30) mixed PP based melt-mixed nanocomposites have been comparatively evaluated with regard to morphological, rheological and thermo-mechanical properties. The ratio of mean free space lengths (L-f) to infiltrated mean free space lengths (L-inf) between nanotubes in isotactic-syndiotactic (70:30) blended matrix based nanocomposites increased relatively indicating a dispersed-morphology. The rheological percolation threshold increased up to a higher extent of MWCNT-NH2 loading (from O-c approximate to 2.3 x 10(-4) in isotactic to O-c approximate to 11 x 10(-4) in iso-syndio blend) accompanied with the formation of a mechanically responsive network structure. van-GurpPalmen plot showed a transition in the rheological response as a consequence of network morphology getting shifted to higher concentration of MWCNT-NH2 in the isotactic-syndiotactic mixed PP based nanocomposites than in the isotactic based one. Constitutive modeling of complex viscosity response of the nanocomposites led to functional correlation between the percolation and relaxation dynamics of polymer chains. POLYM. ENG. SCI., 58:1115-1126, 2018. (c) 2017 Society of Plastics Engineers