Wettability Properties of Biopolymer Coated Urea with Addition of Fillers

Introduction of control release urea (CRU) in agriculture gives good significant impact toward environmental and economic. The main objective of control release urea is to minimize the nutrient loss into soil through leaching and to increase efficiency of nutrient usage. There are many type of coating material has been introduced and applied for control release urea. For this research the biopolymer composite material has been developed as coating material because the biopolymer composite is more environmental friendly compared other coating material. However, the combination of biopolymer coating materials which are starch, polyvinyl alcohol (PVA) and citric acid do not give a good steady released of urea.
Coating uniformity of coated urea is crucial to allow urea to be released at steady rate. The good coating uniformity from thin-film technique needs to have good wettability properties of biopolymer coating material. In order to improve the wettability properties, fillers from Bentonite, Kaolin, Nanoclay Bentonite and Halloysite Nanoclay is mixed at certain percent with other biopolymer coating materials. Thus, the purpose of this research is to study the wettability properties of biopolymer coated urea with addition of fillers. Therefore, wettability properties, contact angle and spreading behaviour is investigated. The experimental matrix is designed by varying the type and percentage of fillers added into biopolymer composite. The wettability properties are characterized by using Optical Contact Angle (OCA) and SCA20 software.