To better understand how plant fibers mechanically defibrillate into cellulose nanofibrils, the wood pulp fiber suspension was processed by refining in combination with intense microfluidization. Cellulose nanofibril properties, including the micro-structure, crystallinity, and degree of polymerization were characterized. Several novel composite materials based on the resulting cellulose nanofibril were prepared and their potential applications were examined. The results showed that intense microfluidization further liberated microfibril bundles (aggregations) created during refining, improving the integral properties of resultant nanofibrils. Nanofibril diameters ranged from 8 to 40 nm while lengths varied over several micrometers, and they exhibited a highly tangling network. Although the original crystal structure was preserved, nanofibril crystallinity decreased to 44%, and the degree of polymerization was reduced by 32% compared to that of pulp fiber. Due to excellent mechanical properties and high light transmittance, free-standing cellulose nanofibril films are considered as promising substrates for flexible integral circuit, LED, and optical materials. Multifunctioned cellulose nanofibril aerogels are highly porous and environmentally friendly, which can be optionally tailored for use of water purification, air filtration, intelligent control and as efficient catalysts.
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