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Molecular Engineering of Fracture Energy Dissipating Sacrificial Bonds Into Cellulose Nanocrystal Nanocomposites
Author(s) -
McKee Jason R.,
Huokuna Johannes,
Martikainen Lahja,
Karesoja Mikko,
Nykänen Antti,
Kontturi Eero,
Tenhu Heikki,
Ruokolainen Janne,
Ikkala Olli
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201401072
Subject(s) - nanocomposite , materials science , nanocrystal , polymer , toughness , supramolecular chemistry , composite material , fracture toughness , nanorod , cellulose , nanomaterials , hydrogen bond , polymer nanocomposite , polymer science , nanotechnology , molecule , chemical engineering , chemistry , organic chemistry , engineering
Abstract Even though nanocomposites have provided a plethora of routes to increase stiffness and strength, achieving increased toughness with suppressed catastrophic crack growth has remained more challenging. Inspired by the concepts of mechanically excellent natural nanomaterials, one‐component nanocomposites were fabricated involving reinforcing colloidal nanorod cores with polymeric grafts containing supramolecular binding units. The concept is based on mechanically strong native cellulose nanocrystals (CNC) grafted with glassy polymethacrylate polymers, with side chains that contain 2‐ureido‐4[1 H ]‐pyrimidone (UPy) pendant groups. The interdigitation of the grafts and the ensuing UPy hydrogen bonds bind the nanocomposite network together. Under stress, UPy groups act as sacrificial bonds: simultaneously providing adhesion between the CNCs while allowing them to first orient and then gradually slide past each other, thus dissipating fracture energy. We propose that this architecture involving supramolecular binding units within side chains of polymer grafts attached to colloidal reinforcements opens generic approaches for tough nanocomposites.