Controlled release on sand bed columns and biodegradability in soil of chitosan: Hydroxypropyl methylcellulose films

Abstract

The main purpose of this work is to prepare and characterize films based on chitosan (Q) and hydroxypropyl methylcellulose (HPMC) blends to achieve adequate properties to be used as coating of conventional fertilizers to prolong their availability for crops. The films loaded with KNO3 as model fertilizer were prepared by casting. Release of fertilizer was studied using sand bed columns. To quantify films durability in soil, their areas were measured in function of time. Results showed that chitosan substantially improved the durability of HPMC, lengthening its permanence in soil 900‰. Relative humidity had influence in mechanical properties. Comparing KNO3 powder and that loaded in the film, the time of residence in the column was much lower for the powder than the second one: 4 and 56 days, respectively. Chitosan–HPMC film would be promising as polymeric coating for controlled release fertilizers taking into account field conditions.