Controlled release formulations have the potential to reduce the environmental problems associated with the conventional application of pesticides. The use of controlled release formulations can, in many cases, increase the duration of activity of agrochemicals, decrease the total amount of agrochemicals, decrease the environmental pollution, save the manpower and energy by reducing the number of applications required in comparison to conventional formulations, increase safety for the farmer and decrease nontarget effects. The aim of this thesis was to fabricate polycaprolactone microfibers and nanofibers containing thiram fungicide and to study the release of thiram from the micro and nanofibers webs. The micro and nanofibrous PCL mat samples produced by electrospinning in this work consisted of 5, 10, 15 and 20% (W/W) thiram. For the microfibers fabrications, solutions consisting of 9,11,13,15 and 17% w/v PCL/ choloroform and thiram were prepared. For the fabrication of the nanofibers, solutions contained 8.5, 9.5 and 10.5% PCL in a solvent system consisting of choloroform- methanol with ratio (v/v) of 70-30 as well as thiram were prepared. The micro and nanofibers were electrospun and then characterized by FESEM, FTIR and XRD. FESEM images showed that by increasing the thiram content, microfibers diameter were reduce. The diameter of nanofibers decreased with an increase in the amount of thiram up to 10% and then increased with an increase in the amount of thiram up to 20%. FTIR analysis indicated that no interaction between PCL and thiram has occurred. The controlled thiram release was studied using spectrophotometer and TGA analysis. Similar results were gained by both technics. It was found that the release rate of thiram was influenced by the type of fibers (micro or nanofibers) and the amount of thiram. The release of fungicide from microfibers formulations occurred through non-Fick diffusion mechanism and from nanofibers formulations through Fick diffusion mechanism. It can be claimed that PCL electrospun micro and nanofibers can be used as controlled release of thiram for agriculture applications.
