title: Polymer Nanocomposites with Cellulose Nanocrystals Featuring Adaptive Surface Groups.
abstract: Cellulose nanocrystals (CNCs) are mechanically rigid, toxicologically benign, fiber-like nanoparticles. They can easily be extracted from renewable biosources and have attracted significant interest as reinforcing fillers in polymers. We here report the modification of CNCs with the 2-ureido-4[1H]pyrimidinone (UPy) motif as an adaptive compatibilizer, which permits the dispersion of UPy-modified CNCs in nonpolar as well as polar media. In toluene, the UPy motifs appear to form intra-CNC dimers, so that the particles are somewhat hydrophobized and well-dispersible in this nonpolar solvent. By contrast, the UPy motifs dissociate in DMF and promote dispersibility through interactions with this polar solvent. We have exploited this adaptiveness and integrated UPy-modified CNCs into nonpolar and polar host polymers, which include different poly(ethylene)s, a polystyrene-block-polybutadiene-block-polystyrene elastomer and poly(ethylene oxide-co-epichlorohydrin). All nanocomposites display an increase of stiffness and strength in comparison to the neat polymer, and some compositions retain a high elongation at break, even at a filler content of 15% w/w.
authors.affiliation: Adolphe Merkle Institute, University of Fribourg , Chemin des Verdiers 4, 1700 Fribourg, Switzerland.
authors.forename: Jens C
authors.initials: JC
authors.lastname: Natterodt
authors.affiliation: Adolphe Merkle Institute, University of Fribourg , Chemin des Verdiers 4, 1700 Fribourg, Switzerland.
authors.forename: Janak
authors.identifier: 0000-0003-3715-5260
authors.initials: J
authors.lastname: Sapkota
authors.affiliation: Virginia Polytechnic Institute and State University (Virginia Tech) , Macromolecules Innovation Institute (MII), Department of Materials Science and Engineering, 203 Holden Hall, 445 Old Turner Street, Blacksburg, Virginia 24061, United States.
authors.forename: E Johan
authors.initials: EJ
authors.lastname: Foster
authors.affiliation: Adolphe Merkle Institute, University of Fribourg , Chemin des Verdiers 4, 1700 Fribourg, Switzerland.
authors.forename: Christoph
authors.identifier: 0000-0001-7183-1790
authors.initials: C
authors.lastname: Weder
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D020724:Elastomers / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D020724:Elastomers; D011108:Polymers; D002482:Cellulose