ARS | Publication request: Preparation and characterization of a novel micro- and nanocomposite hydrogels containing cellulosic fibrils.

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 15, 2011
Publication Date: July 27, 2011
Citation: Aouada, F.A., De Moura, M.R., Orts, W.J., Mattoso, L.H. 2011. Preparation and characterization of a novel micro- and nanocomposite hydrogels containing cellulosic fibrils. Journal of Agricultural and Food Chemistry. (17): 9433-9442.

Interpretive Summary: In recent years, material engineers have embraced the production of green composite materials using cellulose from agricultural biomass because of cellulose is widely abundant, biodegradable, renewable, and has the ability to produce a reinforced polymer material that can compete with synthetic composites in an environmentally benign nature. The main objective of this paper was to report a simple, fast and low cost strategy for the synthesis of micro- and nanocomposites, materials that take advantage of the high surface area of small particles, by adding cellulose nanofibers obtained from agriculturally-derived fibers using acid hydrolysis. When cellulose nanofibers were added to polyacrylamide-methylcellulose (PAAm-MC) hydrogels – a commercial standard in the polymer industry -- the cellulose nanoparticles improved the mechanical and structural properties of the material without negatively impacting their thermal and hydrophilic properties. The value compressive strength of the hydrogel was nearly doubled by the addition of cellulose nanofiber making these hydrogel nanocomposites of potential commercial interest to green manufacturers.

Technical Abstract: In recent years, the preparation of cellulosic composites and nanocomposites has become an important approach because of the wide abundance of cellulose, its biodegradability, renewability, and the ability to effectively reinforce a polymer matrix in an environmentally benign nature. The main objective of this paper was to report a simple, fast and low cost strategy for the synthesis of micro- and nanocomposites by adding cellulose nanofibers, obtained by acid hydrolysis and added to hydrogels as reinforcing agents. When cellulose nanofibers were added to polyacrylamide-methylcellulose (PAAm-MC) hydrogels, morphologic analyses showed significant decreases in pore size and formation of three-dimensional well-oriented porous microstructure. It was also observed that cellulose nanoparticles improved the mechanical and structural network properties without negatively impacting their thermal and hydrophilic properties. The value of maximum compressive stress was 2.1 kPa for the PAAm-MC and it increased to 4.4 kPa when the cellulose nanofiber was incorporated into the hydrogel. By investigation of XRD patterns it was found that the incorporation of cellulose nanofiber affected the crystallinity of PAAm-MC hydrogels, thus contributing to improvements in mechanical, structural and hydrophilic properties of the PAAm-MC hydrogels.