PLA-nanocellulose biocomposites

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).

Solvent casting process is the simplest method for laboratory-scale preparation of PLA/nanocellulose biocomposites. Organic solvents for PLA dissolution such as N,N-dimethylacetamide (DMAc), 26,27,29,32,43,50,51,53,60-63... 

Nanocelluloses have been used as a nucleating agent to accelerate the erystallization rate of PLA. PLA/nanocellulose biocomposites frequently exhibit signifieantly improved thermal and mechanical and various other properties eompared to those of pure PLA. The tensile modulus and strength of neat PLA are generally improved with an increase of nanocellulose content. Inereased storage modulus at temperatures above Tg is often observed with the ineorporation of nanoeellulose in PLA, as well as decreased gas permeability. 

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... 

Kose and Kondo studied tbe size effects of cellulose nanofibres on the crystallization behaviour of PLA. They discovered that the smaller size of cellulose nanofibres on tbe nanoscale does not necessarily make a better nucleating agent for PLA. Table 9.1 summarizes the Avrami kinetic parameters for the isothermal crystallization of the PLA and PLA biocomposites with different types of nanocelluloses as compared to PLA composites with talc and nanoclay. With the addition of unmodified and silylated CNCs as nucleating agents, the t 2 value increases with increasing T similar to that of nanoclay and com starch, but opposite to that of talc. Comparing the... 

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