Rice Husk Based Biodegradable Cardboards for Packaging Applications

Rice husk, also known as rice hull, is a byproduct created in the production of rice. With over 500 million tons of rice produced yearly in the world, the supply of rice husk is very high while the usage of it is low. Although United States accounts for only 2% of global rice production, it has become the World’s fifth largest exporter with more than 6% of global exports. In 2019 alone, the state of Arkansas has harvested rice in 1,126,000 with an average yield of 7480 pounds per acre. Dried paddy yields around 20% of hull, 15% of stalk and 10% of bran. Taking advantage of this huge sustainable yield, this study focuses on developing the biodegradable cardboard utilizing the discarded rice husk that can be used for packaging applications while lowering the amounts of conventional pulping material. Rice husk contains about 15-25% lignin and 35-40% cellulose and is coarse and abrasive in nature. Hence, the rice husk is softened initially to make it into pulp. This study is aimed to determine the tensile and compressive strength of the paper. Hence, pretreatment of rice husk is performed by using various concentrations of NaOH and the effective pretreatment was observed at 2g of NaOH with 1000 ml of water for 100gms of ricehusk. The mixture thus obtained is blended into pulp and is placed in the trays to dry. When blended and softened, the husk alone was not able to hold any shape when tested in paper making molds. Hence, binding agent was added to the pretreated rice husk to hold the rice husk together and to improve the strength of the specimen. Four specimens were prepared by adding 5g of starch reagent, 5g of tapioca starch, 5g of clear elmers glue and 5g of starch reagent and 5g of elmers glue together. The specimen with tapioca starch was the weakest whereas the specimen with elmers glue and starch reagent was the strongest. The optimization tests with varying amounts of glue and starch reagent were in progress and the tensile and compressive strengths of the cardboards are yet to be determined. However, the studies showed favorable results suggesting that the rice husk together with biodegradable additives can be used to make cardboards for packaging applications.