Cellulose nanowhiskers preparation

Rosa, M., Medeiros, E., Malmonge, J., Gregorski, K., Wood, D., and Mattoso, L. (2010). Cellulose nanowhiskers from coconut husk fibers Effect of preparation conditions on their thermal and morphological behavior, Qarboh Qf f]x., 81,83-92. 

PEG/Cellulose Nanowhiskers (CNW) -The adhesion of PEG to the natural fibers can explain the lubricating effect of PEG in the preparation of composites with PHB and natural fibers. [39]... 

Oat spelt arabinoxylan was used for nanocomposites with cellulose nanowhiskers (CNW) [65-68]. Films prepared from oat spelt arabinoxylan alone have poor film forming ability, which has been attributed to insufiicient chain length of the polymer, high glass transition temperature, or poor solubility. The... 

Jiang L, Morelius E, Zhang J et al (2008) Study of the poly(3-hydroxybut3oate-co-3-hydroxyvalerate)/ cellulose nanowhisker composites prepared by solution casting and melt processing. J Cranpos Mater 42 2629-2645... 

M.F. Rosa, E.S. Medeiros, J.A. Malmonge, K.S. Gregorski, D.F. Wood, L.H.C.Mattoso, G.Glenn, W.J. Orts, and S.H. Ima, Cellulose nanowhiskers from coconut huskfibers Effect of preparation conditions on their thermal and morphological behavior. Carbohydr. Polym. 8, 83-92 (2010). 

Hossain, K.Z., Ahmed, I., Parsons, A., Scotchford, C., Walker, G., Thielemans, W., et al. Physico-chemical and mechanical properties of nanocomposites prepared using cellulose nanowhiskers and poly(lactic acid). J. Mater. Sci. 47, 2675-2686 (2012)... 

CO-3-hydroxy valerate) (PHBV) and cellulose by extrusion blending, using a co-rotating twin screw extruder with a temperature profile ranging from 160 to 145 °C. PHBV pellets were dried, dry mixed with a cellulose nanowhisker powder and extruded. The extrudate was cooled in a water bath and the final pellets were dried. This material did not have the same mechanical properties and the same cellulose dispersion as the analogous composite prepared with solvent casting process. It was necessary to add a compatibilizer to improve the dispersion. 

Jiang et al. (2008) prepared a composite material from PHBV and cellulose using solvent casting. They dissolved PHBV, cellulose nanowhiskers and polyethylene glycol (as a compatibilizer) in A,A-dimethylformamide (DMF), and cast the solution on a glass plate at 50 °C in order to realize DMF evaporation. The final material showed a homogeneous dispersion of cellulose nanowhiskers, which improved mechanical properties. 

Figure 5.2 TEM micrograph showing exfoliated distribution of cellulose nanowhiskers in a PHBHV matrix nanocomposite prepared hy the solution intercalation method.

The main objective of this chapter is to provide a snapshot of the rapidly developing nanocomposite materials based on PLA. To date, various types of nanoreinforcements such as nanoclay, cellulose nanowhiskers, ultrahne layered titanate, nanoalumina, carbon nanotubes [13-19], and so on have been used for the preparation of PLA nanocomposites. For each particular system, progress is discussed chronologically, beginning with the pioneering work. Various physicochemical characterization and improved mechanical properties are summarized. Ongoing developments and promises are also discussed. Finally, possible suitable applications and future prospect of nanocomposites based on PLA are described. 

Ten E, Jiang L, Wolcott MP (2013) Preparation and properties of aligned poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/cellulose nanowhiskers composites. Carbohydr Polym 92 206-213 Ten E, Turtle J, Bahr D, Jiang L, Wolcott M (2010) Thermal and mechanical properties of poly(3-hydroxybutyrate-co-3-hydrox5Tvalerate)/cellulose nanowhiskers composites. Polymer 51 2652-2660... 

Figure 3.6 Photographic demonstration of the shape recovery of the composite prepared with 12 wt% cellulose nanowhiskers (a) temporary shape fixed in the dry and cool state (elongation of around 300%) (b) temporary shape after stimulation with heat (c) temporary shape after stimulation with cool water (d) original shape after stimulation with hot water (68°C). From Luo et al. [42], with permission.

The PLA layered silicate nanocomposites were prepared by adding small amounts of the compatibilizer to form the randomly distributed intercalated silicate layers. Simple melt extmsion of PLA and organically modified montmorillonite lead to better parallel stacking of silicate layers and much stronger flocculation due to hydroxylated edge-edge interactions of silicate layers and consequently improved mechanical and barrier properties, which makes it suitable for food packaging applicatioa Fmther, Bondeson et al. used melt extmsion to fabricate a transparent bio-based nanocomposite of 5 wt% cellulose nanowhiskers (CNW) and cellulose acetate butyrate (CAB), plasticized by triethyl citrate (TEC) (2007). 

Cellulose nanowhiskers (CNWs) have been obtained from a variety of matrices such as cotton [63], sisal [64], and coconut husk fibers [65]. Other alternative sources of cellulose nanofibrils includes naturally colored cotton, curaua (Ananas erecti-Jblius), and sugarcane bagasse have been successfully used to prepare nanowhiskers [66-69]. 

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