Free radical graft copolymerization of nanofibrillated cellulose with acrylic monomers

Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

“…Chemical surface modification efficiently tackles this problem (Habibi 2014). Among the many different routes for surface modification reported, esterification with acetic anhydride or long chain carboxylic acids (Rodionova et al 2010;Lee et al 2011;Bulota et al 2012);grafting of polymers (Lönnberg et al 2008;Littunen et al 2011;Missoum et al 2012);cationization (Hasani et al 2008;Syverud et al 2010); silylation (Goussé et al 2004;Andresen et al 2006;Lu et al 2008a, b), and TEMPO oxidation (Saito et al 2006;Fukuzumi et al 2009) are mentioned as important examples. Even though highly successful at the laboratory scale, the up-scaling of these wetchemical approaches to industrial dimensions, involving partly pricey reagents and repeated solvent transfers is most probably quite cost-intensive.…”

Surface functionalization of nanofibrillated cellulose using click-chemistry approach in aqueous media

“…Apart from the cellulosic components, the nanofibrillated reference sample was found to have elevated aliphatic C-C components in the high resolution XPS measurements. This has actually been the case for all the published XPS nanocellulose studies (Andresen et al 2006(Andresen et al , 2007Uschanov et al 2011;Littunen et al 2011). This phenomenon seems to be connected with the route used in drying nanofibrillar cellulose materials.…”

Bacterial cellulose nanowhiskers to enhance the properties of plastics and bioplastics of interest in food packaging

“…PGMA-grafted BCNW were prepared according to a previously published study (Littunen et al, 2011). Partially hydrated BCNW were diluted with water to obtain a 0.2 wt.-% suspension and the pH was adjusted to 1 with dilute nitric acid.…”

“…Surface chemical modification by reaction of the hydroxyl groups present on the surface of cellulose nanocrystals with organomodifying agents has been proposed as one approach to overcome this shortcoming. In this regard, CNW have been successfully modified by acetylation (Goffin et al, 2011a;Sassi & Chanzy, 1995;Tomé et al, 2011), oxidation (Cao et al, 2012;Montanari et al, 2005), silanization (Goussé et al, 2002;Pei et al, 2010;Raquez et al, 2012) and polymer grafting reactions (Cao et al, 2009;Goffin et al, 2011a, b;Littunen et al, 2011;Shukla & Athalye, 1995) and incorporation of modified CNW into polymeric matrixes, such as PLA has also been reported (Goffin et al, 2011a;Lin et al, 2011;Pei et al, 2010;Raquez et al, 2012;Tomé et al, 2011).…”

“…The epoxy group in the GMA chains was expected to react with the carboxylic group of PLA, thus promoting interfacial adhesion between BCNW and the polyester matrix. While cellulose modification by graft copolymerization of (GMA) has been reported (Littunen et al, 2011;Shukla & Athalye, 1995), information on the incorporation of the grafted filler into polymeric matrixes is lacking. The morphology, thermal properties, oxygen barrier, water affinity and mechanical properties of BCNW and BCNW-PGMA loaded PLA nanocomposites were investigated and compared to determine the influence of surface modification on the nanocomposites performance.…”