Rice Hulls as a Cushioning Material

Abstract

Rice hulls are a by-product of rice production. It is light, bio-degradable, difficult to burn and less likely to allow moisture to propagate. In this study, rice hulls were used as a cushioning material inside a plastic tote. Its impact absorption property was compared to a 3/16-inch bubble wrap and a 0.129-inch anti-vibration rubber pad. From the same baseline, 1-inch thick rice hulls reduced impact acceleration by 25% as compared with 39% and 42% of bubble wrap and anti-vibration pad with the same thickness, respectively. When wet, rice hulls became denser. Thus, the impact increased at the rate of 0.054% per 1% increase of water per hull weight. To make the use of rice hulls practical, rice hulls were placed in sealed plastic bags. Sealed bags containing rice hulls reduced impact acceleration by 41%, which was comparable with the bubble wrap case due to trapped air inside the sealed plastic bag. Using bubble wraps would be more economical and practical. However, bubble wraps could burst and cushioning property would be lost. A sealed plastic bag with rice hulls inside could burst, but the rice hulls would provide another line of protection. In addition, rice hull is a good thermal insulating material and would be useful in protecting some temperature-sensitive products during the distribution by placing bagged rice hulls in all sides of a tote or box.