Competition between supernucleation and plasticization in the crystallization and rheological behavior of PCL/CNT-based nanocomposites and nanohybrids

16 pags., 14 figs., 4 tabs.PCL was blended with pristine multiwalled carbon nanotubes (MWCNT) and with a nanohybrid obtained from the same MWCNT but grafted with low molecular weight PCL, employing concentrations of 0.25 to 5 wt % of MWCNT and MWCNT-g-PCL. Excellent CNT dispersion was found in all samples leading to supernucleation of both nanofiller types. Nanohybrids with 1 wt % or less MWCNTs crystallize faster than nanocomposites (due to supernucleation), while the trend eventually reverses at higher nanotubes content (because of plasticization). Rheological results show that yield-like behavior develops in both nanocomposites, even for the minimum content of carbon nanotubes. In addition, the MWCNT-g-PCL family, when compared with the neat polymer, exhibits lower values of viscosity and modulus in oscillatory shear, and higher compliance in creep. These rheological differences are discussed in terms of the plasticization effect caused by the existence of low molecular weight free and grafted PCL chains in the nanohybrids. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1310–1325.The authors acknowledge funding support from: the Spanish Ministerio de Economıa y Competitividad (MINECO) for the Project: MAT2012-36341-FEDER, Decanato de Investigación y Desarrollo Universidad Simón Bolívar DID G02. The POLYMAT/ UPV/EHU team acknowledges funding from the following projects: “UPV/EHU Infrastructure: INF 14/38”; “Mineco/ FEDER: SINF 130I001726XV1/Ref.: UNPV13–4E10–1726,” and “MinecoMAT2014–53437-C2-P.” R. A. Pérez-Camargo gratefully acknowledges the award of a PhD fellowship by POLYMAT Basque Center for Macromolecular Design and EngineeringPeer Reviewe