Making Nanocomposites of Hydrophilic and Hydrophobic Polymers Using Gas‐Responsive Cellulose Nanocrystals

Abstract

Generally, different surface‐functionalized cellulose nanocrystals (CNC) are required for use as nanofillers in hydrophilic and hydrophobic polymers. In the present study, for the first time, a kind of “universal” nanofiller for polymer composites is demonstrated by using CNC grafted with a gas‐responsive polymer. CNC are functionalized with pyrene‐containing poly(2‐(N,N‐diethylaminoethyl)methacrylate) (CNC‐g‐PDEAEMA‐Py). The reversible transport of the nanocrystals between phase‐separated water and toluene is proved by nuclear magnetic resonance (1H NMR) and fluorescence spectroscopy. On the one hand, water‐soluble poly(vinyl alcohol) (PVA) can be mixed with dispersed CNC upon CO2 bubbling for making the PVA‐CNC nanocomposite. On the other hand, after the transfer of CNC into the toluene solution upon N2 bubbling, styrene‐butadiene‐styrene (SBS) triblock copolymer can be dissolved for the SBS‐CNC nanocomposite. In both systems, CNC are well dispersed, having an effect on the mechanical and shape memory properties of SBS and PVA, respectively.