Release of Cellulose Nanocrystal Particles from Natural Rubber Latex Composites into Immersed Aqueous Media

In the current study, we focused on the preparation of nanocomposite films of natural rubber latex-cellulose nanocrystals (NR/CNCs) and investigated the release of CNCs from those materials into aqueous solutions. The obtained nanocomposite films were well characterized for further understanding of the release mechanism; as the intermolecular interactions between the two components were studied by Fourier-transform infrared spectroscopy, the morphology was studied with scanning electron microscopy, and nanostructures were analyzed by tensile and dynamic mechanical testing. The release behavior of CNCs from the NR/CNCs nanocomposite films was studied by a fluorescent labeling technique, and the release process in various media was modeled by first-order kinetics. Higher contents of CNCs in the nanocomposite films and a relatively acidic or alkaline medium facilitated the release process, while higher ionic strength of the media could hamper the release of CNCs from the nanocomposite films. In this study, our objective was to transport CNC particles from NR/CNC composites into immersed media to be used beneficially in biomedical applications. Nevertheless, in other surroundings, the release of CNCs or any other nanoparticles from composite materials may not be desirable. Hence, this study also provides a protocol to investigate the release of nanoparticles from a host matrix into the surrounding media and also promotes a rethinking of the nanoparticle release issue from composites to the environment.