Abstract
The microscopic origin of mechanical enhancement in polymer nanocomposite (PNC) melts is investigated through the combination of rheology and small-angle neutron scattering. It is shown that in the absence of an extensive particle network, the molecular deformation of polymer chains dominates the stress response on intermediate time scales. Quantitative analyses of small-angle neutron scattering spectra, however, reveal no enhanced structural anisotropy in the PNCs, compared with the pristine polymers under the same deformation conditions. These results demonstrate that the mechanical reinforcement of PNCs is not due to molecular overstraining, but instead a redistribution of strain field in the polymer matrix, akin to the classical picture of hydrodynamic effect of nanoparticles.
Original language | English |
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Article number | 117801 |
Journal | Physical Review Letters |
Volume | 126 |
Issue number | 11 |
DOIs | |
State | Published - Mar 16 2021 |
Funding
This work was supported, in part, by the Ralph E. Powe Junior Faculty Enhancement Awards from Oak Ridge Associated Universities. Y. W. acknowledges support by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Early Career Research Program Award KC0402010, under Contract No. DE-AC05-00OR22725. Part of this work was conducted at ORNL’s Center for Nanophase Materials Sciences, which is a U.S. Department of Energy Office of Science User Facility. The SAXS measurements were performed at Beamline 12-ID-B of Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Access to NGB 30m SANS was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. Certain commercial equipment, instruments, or materials are identified in this document. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology nor does it imply that the products identified are necessarily the best available for the purpose.