Controlled release of indole-3-butyric acid (RBA) - based on polymeric matrix prepared by ionizing radiation

Polyacrylamide/polyethylene oxide (PAAm/PEO) controlled release matrices were designed to obtain a better control over the concentration of indole-3-butyric acid (IBA). PAAm/PEO incorporated IBA was prepared by exposing aqueous solutions of PEO, PAAm, crosslinking agent N,N'-methylene-bisacrylamide, and IBA mixtures to electron beam irradiation. PAAm/PEO copolymer structural property relationships that affect its controlled release behavior were determined. Analysis of the results obtained indicated that it is possible to optimize IBA controlled release by adjusting the dimensions and crosslinking degree of the copolymer as well as the concentration of the incorporated IBA. The crosslinking degree of the copolymer can be controlled by governing the irradiation dose, polymer blend composition and/or the amount of crosslinking agent. IBA release rates have been investigated as a function of environmental conditions, such as the changes in pH and temperature to determine the factors, which mostly contribute to the release of IBA. The effect of PAAm/PEO-IBA matrix on the average height of corn (Zea mayz) plant was investigated. The results obtained, revealed that PAAm/PEO-IBA systems have a capability to deliver IBA slowly and continuously. As a result, the development of root and vegetative systems of Zea mayz plant was greatly promoted. Copyright (C) 2004 John Wiley Sons, Ltd.