Elementary nanocrystallites

Microfibrillar structure of cellulose. Cr, elementary nanocrystallite A, amorphous noncrystalline domain. 

Parallel orientation of the microfibrils in the S2 layer under an acute angle toward the fiber axis imparts to natural cellulose fibers increased axial mechanical properties. The microfibrils of the cell wall consist of elementary nanofibrils, and each such nanofibril is built of ordered nanocrystallites and low ordered noncrystalline (amorphous) domains statistically alternated along the fibril (Figure 9.3). 

A two-phase model containing crystalline and noncrystalline domains is currently used to describe the stmctural organization of cellulose (Krassig, 1993). Further investigations also revealed the presence on the surface of crystallites a paracrystalline fraction that must be taken into consideration in an improved model of cellulose structure (loelovich et al., 2010). Statistically alternated nanocrystallites along with nanoscale noncrystalline domains are integral constituents of long and thin elementary fibrils and their bundles—microfibrils. 

Cellulose is a nanostructured natural polymer that has a complicated multilevel structural organization. The linear cellulose macromolecules joined by hydrogen bonds form the nanocrystallites, nanoscale non-crystalline domains and elementary nanofibrils. The elementary nanofibrils are aggregated into bundles called... 

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