Due to the shortage of petroleum reserves, the importance of developing lignocellulosic biomass for the production of fuel and chemicals that offer economic, environmental, and strategic advantages has been increasingly emphasized. Hemicelluloses, as the non-cellulose polysaccharides in plant cell wall, represent an immense renewable resource of biopolymers. Alkaline hemicellulose extraction was conducted in this research and was found to be impacted by a prior delignification step differently for different biomasses. Extraction of pine is very sensitive to the presence lignin whereas switchgrass and poplar were not. An acceptable hemicellulose extraction efficiency (switchgrass 55.5%, poplar 50.7%) could be achieved with 10% NaOH extraction from switchgrass and poplar without prior delignification. For pine, a prior sodium chlorite delignification resulted in the subsequent extraction of more than 50% of the original hemicellulose in the biomass; a striking contrast to without delignification, where only 3.4% of hemicellulose could be extracted. The use of hemicellulose as a biobased component of super-absorbent hydrogels has strong commercial and environmental advantages of being low cost, renewable, and biodegradable. Hemicellulose-based hydrogels were produced by free radical polymerization with acrylic acid (AA) and acrylamide (AM) in the presence of initiator and crosslinking agents. Higher AA content and AM content in the products resulted in higher water absorbency. Hemicellulose-based hydrogel produced with 23.5% by weight of hemicellulose achieved ~300 g/g water absorbency, ~40 g/g saline absorbency, which is comparable with that of hydrogels produced with only the base components of petroleum-based acrylic acid and acrylamide (water absorbency of 415 g/g and saline absorbency of 50.1 g/g).

Extraction and modification of hemicellulose to produce high value super absorbent gels

2019 Spring National Meeting

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