Achieving Enhanced Interfacial Adhesion and Dispersion in Cellulose Nanocomposites via Amorphous Interfaces

Wenjie Xia*, Xin Qin, Yao Zhang, Robert Sinko, Sinan Keten

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

Understanding and designing nanoscale interfaces are essential to advancing the thermomechanical performance of polymer nanocomposites reinforced by nanocellulose. In this context, it remains to be understood how disorder introduced on the surfaces of crystals as filler materials during extraction and processing influences interfacial adhesion with glassy polymers. Using atomistic molecular dynamics (MD) simulations, here we systematically explore the interfacial adhesion between nanocellulose and poly(methyl methacrylate) (PMMA) by comparing an ordered cellulose nanocrystal (CNC) interface to a disordered amorphous cellulose (AC) interface. Using a bilayer system that consists of a cellulose underlayer and a polymer upper layer, our simulations show that the AC-PMMA interface can achieve about 50%-60% greater interfacial adhesion energy than that of the CNC-PMMA interface. We uncover that the improved adhesion primarily arises from a larger number of hydrogen bonds formed between the cellulose and polymer chains. Remarkably, the greater adhesion energy and smaller filler-filler surface energy achieved by the AC lead to significantly improved dispersive capability of nanofiller in polymer matrices in comparison with the CNC. Further analyses reveal that while the polymer chain configurations are characteristically different near the two interfaces, where stronger ordering and denser packing of chains are observed near the CNC, their relaxation dynamics are quite similar for the two interfaces. We attribute this observation to the competing effects between the interfacial adhesion and chain packing on polymer relaxation. Our study provides fundamental insights into the interfacial mechanisms of polymer-nanocellulose interfaces at a molecular level and reveals that surface disorder inevitably introduced during production may serve to improve interfacial adhesion energy with the polymer matrix while also enhancing nanofiller dispersion within polymer nanocomposites.

Original languageEnglish (US)
Pages (from-to)10304-10311
Number of pages8
JournalMacromolecules
Volume51
Issue number24
DOIs
StatePublished - Dec 26 2018

Funding

W.X. gratefully acknowledges support from the NSF through the ND EPSCoR (Award #FAR0021960) and Department of Civil and Environmental Engineering and College of Engineering at North Dakota State University (NDSU). S.K. acknowledges support from the PECASE (Award #N00014163175). The authors also acknowledge support from the National Institute of Standards and Technology (NIST). Supercomputing grants from the CCAST Thunder HPC System at NDSU and the Quest HPC System at Northwestern University are acknowledged.

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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