Applications of cellulose nanomaterials from cotton ginning byproducts

Authors: Jordan, Jacobs; Easson, Michael; Cheng, Huai

Submitted to: American Chemical Society SE/SW Regional Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/29/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The recent trend away from petroleum-based products and additives is due to a shift towards green and sustainable chemistry, where petroleum-based additives suffer from acute toxicity and persistent environmental concerns. Biopolymers as replacements, on the other hand, are abundantly available, renewable, and sustainable. Cellulose is the most abundant biopolymer on earth and is the chief structural component of the primary cell walls of plants, and can be chemically, enzymatically, and mechanically processed into cellulose nanofibers (CNFs) and nanocrystals (CNCs). However, the production of CNFs and CNCs is often from highly purified cellulose which has been oxidatively bleached to remove lignin and other components. To meet the needs of reduced cost, CNFs and CNCs were prepared through a variety of chemical processes from cotton gin motes (CGM) and cotton gin trash (CGT). Given the millions of tons of CGT and the hundreds of thousands of tons of CGM available, these two agricultural by-products are promising biomass feedstocks for further value-added applications and offer an enormous, but presently undeveloped, biomass feedstock for production of nanocellulose. Two such disparate applications are presented here: In part, CNCs and CNFs were applied as performance additives tested with cottonseed protein as a paper strength modifier. Cottonseed protein is another biopolymer that has been used in films, adhesives, and paper products as a reinforcement additive. Improved tensile strength, modulus, and elongation at break were observed when the cottonseed protein was used at 10% giving improvements of 87% (modulus) and 97% (tensile strength). When 2% or 10% additive of CNFs or CNCs, respectively, were used the modulus improved 117–122% and the tensile strength improved 127–141%. Furthermore, when lignin-containing CNFs (LCNFs) were used the improvement in modulus and tensile strength were 130% and 167% respectively. These LCNFs have a longer degree of polymerization and were not oxidatively bleached, both reducing cost and eliminating waste products. Finally, CNCs and CNFs have high specific surface area and an abundance of functional groups which can be readily modified to incorporate additional functionality. CNFs have thus been explored as scaffolds for the development of biosensor substrates for the detection of elastase. Elastase activity was detected in vitro through a fluorescence response generated from the cleaving of 7-amino-4-methylcoumarin from a CNF-bound peptide substrate.