Cellulose-based nanocomposites prepared via mini-emulsion polymerization: Understanding the chemistry of the nanocellulose/matrix interface

The miniemelusion polymerization of acrylic monomers in the presence of cellulose nanocrystals (CNCs) and methacryloxypropyl trimethoxysilane (MPMS) as a coupling agent is proven to be an efficient approach for the one-pot synthesis of a ready-for-use stable nancomposite dispersion. In order to gain further insight on the location of the coupling agent within the polymer particles and understand how the silane coupling agent affects the degree of binding between the CNC and the polymer matrix, liquid and solid state NMR (13C and 29Si) investigation were carried out on the nanocomposite. It was shown that the sol fraction contained only the styrene/ethylehexylacrylate (ST/EHA) copolymer, while the CNCs and the MPMS moiety were accumulated on the gel fraction. Based on the analysis, it was concluded that the MPMS is mostly located at the interface of the CNCs and the copolymer matrix.