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Generally, chemical fertilizer is considered as a one of the most significant materials for increasing food production. However, the fast release of the conventional fertilizer could effect negatively on the plants. Thus, the idea of using controlled release method in the agriculture application has emerged recently due to the efficiency of fertilizers can be improved by the controlled-release method. The objective of this work is to synthesize a new Slow Release Fertilizer from three different materials; the first one is urea, which is the conventional fertilizer, the second one is the rice husk (RH), which represents the carrier material, and the third one is epoxidized natural rubber (ENR-50), which represents the coating material. This work was divided into three series. The first series is the production of RH/Urea beads. RH was treated with alkaline NaOH at 1wt.% according to the weight of RH. The treated RH was then mixed with urea that produced treated RH/urea beads. In the second series, 200 mg of ENR-50 was applied to produce thicknes of coating material for treated RH/urea beads. In the third series, treated RH/urea beads coated with 200 mg of ENR-50 were subjected to the released behavior at different temperature in the water. After that, the prepared samples were characterized using Scanning Electron Microscopy (SEM) and UV-visible spectroscopy. Results suggested that the increasing of temperature has increased the rate of urea release of SRF samples in the water. Furthermore, the SRF sample at 35, 45, and 55 °C showed shorter time of release at 40, 34, and 17 day as compared to 47 day of SRF at room temperature.

This synthesis and characterization of slow release material from epoxidized natural rubber (ENR) and rice husks (RH) composites was conducted. The alkali modification of rice husks was carried using different NaOH concentration. ENR-50 and RH composites were analyzed by FTIR. Furthermore, the release behavior of the composites was invistigated using UV-visible spectroscopy. From the purified ENR-50, it can be characterized the peak epoxide group identified at 875 cm-1 and for the isoprene at 835 cm-1. For RH/urea beads, the CH2 peak of cellulose was obtained at 1457 cm-1. However, the CH2 is overlapped with cellulose at 1741 cm-1 and 1726 cm-1 that resulted for the partial opening of epoxide ring from carbonyl peak for hemi-cellulose and lignin, there are C=C stretching from aromatic group can be obtained at 1512 cm-1 and 1595 cm-1. The release of the composite at 7% NaOH concentration was higher than the composite at 1% NaOH concentration.

In this study, the influence of Trans- Polyoctylene Rubber (TOR) as a compatibilizer on the cure characteristics, tensile and physical properties of ENR-25/rSC vulcanizate were determined. Five different loading of TOR (2, 4, 6, 8 and 10 phr) were prepared and added into the vulcanizate. Results indicated that the scorch time (t 2 ) and cure time (t 90 ) bacame shorter as TOR increased, while minimum torque (M L ) and maximum torque (M H ) increased. The incorporation of TOR with the vulcanizates enhanced the tensile strength (T s ), modulus (M100) crosslinking density and hardness values. However, the elongation at break percentage of compatibilized vulcanizates became lower than uncompatibilized vulcanizates.