Polymer Nanocomposites with Cellulose Nanocrystals Featuring Adaptive Surface Groups

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• 作者：Jens C. Natterodt ; Janak SapkotaE. Johan Foster ; Christoph Weder
• 刊名：Biomacromolecules
• 出版年：2017
• 出版时间：February 13, 2017
• 年：2017
• 卷：18
• 期：2
• 页码：517-525
• 全文大小：626K
• ISSN：1526-4602

文摘

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.