Recent strategies for expanding the commercial potential of lignocellulosic (bio)composites and nanocomposites are reviewed with the focus on processes that could compete economically in commodity markets. For example, the high cost of creating and separating nanocrystalline cellulose fibrils at a viable commercial scale has prevented their wide-scale adoption. This was addressed in a series of studies where nanofibrils were isolated using the enzyme-rich digestate from a commercial-grade anaerobic digestor – a “cost-free” source of (unspecified) enzymes. Fiber pulps which were incubated for 5, 10, and 20 days in the enzyme-rich liquid supernatant isolated from a mesophilic anaerobic digestor resulted in marked changes in morphology, crystallinity, and thermal stability of fibrils, eventually creating nanofibrils. Results from DSC, x-ray analysis and microscopy showed that enzymatic hydrolysis likely favored removal of amorphous domains. Another low-cost approach for making (nano)composites involved thermal-treatment of pulps. In a series of studies, fibrils from different biomass sources were heat-treated at 200-300°C in a process called torrefaction, and  were used as fillers/modifiers in place of typical plastic additives with some unique results. Addition of 5% ground torrefied walnut and almond shells, for example, into commercial-grade polypropylene increased its heat distortion temperatures; i.e., its practical softening point, by 8–24<sup>o</sup>C compared with neat polypropylene. It also increased flexural modulus by up to 40%, accompanied by a moderate increase in glass transition temperature. In this review, we present several studies exploring how properties of thermally-treated fibrils vary by source and size (altered via grinding toward the nano-scale), making them uniquely applicable in various potential commercial applications including (1) as additive in commodity (bio)plastics, (2) in car tires as a carbon black displacement, (3) as filtering media for water treatment via activation, and (4) as an ammendment in soils. This presentation will explore processing methods that meet the low cost-points required to enter high volume commodity markets.

Creating cost-effective agriculturally-derived nanocomposites for commodity applications

253rd National Meeting (2017)

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