Nanocellulose surface modification

Figure 9.2 Surface modification chemistries of nanocellulose for PLA/nanocellulose biocomposites, a, Acetylation b, Esterification with various organic acids c, d, e, Grafting of PCL, PLA, P(CL-fi-LA) f, Silanization g, Silylation h, Carbojymethylation combined with hexanoation i, PEG grafting j, Modified with polyhedral oligomeric silsesquioxane (POSS).

Keywords Polymers, nanocellulose, nano composites, surface modification, in-situ polymerization, mechanical properties, biodegradation, scanning electron microscopy (SEM)... 

While techniques for preparation of nanocellulose-reinforced nanocomposite are different in complexity, they typically involve physically mixing and dispersing the nanocellulose and resin in a solvent system. In many cases, solvent exchange techniques are used, often along with surface modification of nanocellulose to make it compatible with organic solvents and/or the resin system. In this context, nanocomposite films from nanocellulose generally are prepared through three various techniques as below ... 

The mechanical properties of PLA/nanocellulose biocomposites are also strongly affected by the processing strategy and surface chemical modification of nanocellulose. Table 9.2 provides an overview of modulus, tensile... 

A summary of the different chemical modification techniques used to alter the surface characteristics of nanocellulose can be found in reference [47]. 

Chemical modification on nanocelluloses stru les with one major challenge—to run reaction of modification so that it changes only the surface of nanosubstrate, while the original morphology... 

Dufresne et al. [153] noted that surface adsorption of potyojq ethylene chains on the surface nanocrystals can improve dispersibility and thermal stability of nanocrystals during the melt processing of polyethylene based nanocomposites. The chemical modification of cellulose is a most effective approach to avoid irreversible agglomeration during drying, and enhance the adhesion between nanocellulose and nonpolar matrices [132]. Dufresne et al. [98] showed also, that chemical and physical compatibilization imparted by poly(ethylene glycol) and polyoxyethylene layers promoted the interfacial interaction between cellulosic nanoparticles and polystyrene. 

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