Forming Covalent Crosslinks between Polymer‐Grafted Nanoparticles as a Route to Highly Filled and Mechanically Robust Nanocomposites
Name
Kubiak et al Adv. Func. Mat. 2019.pdf
Description
Accepted version
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675.82 KB
Format
Adobe PDF
Checksum (MD5)
6b466e7b7162b63cf44f58fee9d293e6
Author(s)
Kubiak, Joshua M
Macfarlane, Robert J
Date Issued
August 2019
Journal
Advanced Functional Materials
Publisher
Wiley
Citation
Kubiak, Joshua M. and Robert J. Macfarlane. “Forming Covalent Crosslinks between Polymer‐Grafted Nanoparticles as a Route to Highly Filled and Mechanically Robust Nanocomposites.” Advanced Functional Materials, 29, 44 (August 2019): © 2019 The Author(s)
Version
Author's final manuscript
Abstract
Filler aggregation in polymer matrix nanocomposites leads to inhomogeneity in particle distribution and deterioration of mechanical properties. The use of polymer-grafted nanoparticles (PGNPs) with polymers directly attached to the particle surfaces precludes aggregation of the filler. However, solids composed of PGNPs are mechanically weak unless the grafted chains are long enough to form entanglements between particles, and requiring long grafts limits the achievable filler density of the nanocomposite. In this work, long, entangled grafts are replaced with short reactive polymers that form covalent crosslinks between particles. Crosslinkable PGNPs, referred to as XNPs, can be easily processed from solution and subsequently cured to yield a highly filled yet mechanically robust composite. In this specific instance, silica nanoparticles are grafted with poly(glycidyl methacrylate), cast into films, and crosslinked with multifunctional amines at elevated temperatures. Indentation and scratch experiments show significant enhancement of hardness, modulus, and scratch resistance compared to non-crosslinked PGNPs and to crosslinked polymer films without nanoparticle reinforcement. Loadings of up to 57 wt% are achieved while yielding uniform films that deform locally in a predominantly elastic manner. XNPs therefore potentially allow for the formulation of robust nanocomposites with a high level of functionality imparted by the selected filler particles.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
https://doi.org/10.1002/ADFM.201905168
