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The use of controlled release fertilizer (CRF) has become a new trend to minimize environmental pollution. In this study, urea-kaolinite containing 20 wt% urea after one hour dry grinding was mixed with different concentrations of chitosan as a binder to prepare nitrogen-based CRF. Fourier transform infrared spectroscopy confirmed the hydrogen bonding between urea and kaolinite. Covalent interaction between urea-kaolinite and chitosan make the granules stronger. The nitrogen release was measured in 5 days interval using a diacetylmonoxime calorimetric method at a wavelength of 527 nm. The results illustrated that by increasing the chitosan concentration from 3 to 7.5%, nitrogen release decreased from 41.23 to 25.25% after one day and from 77.31 to 59.27% after 30 days incubation in water. Compressive stress at break tests confirmed that granules with chitosan 6% had the highest resistance and were chosen for ammonia volatilization tests. Ammonia volatilization was carried out using the forced-draft technique for a period of 10 weeks. The results showed that the total amount of ammonia loss for conventional urea fertilizer and urea-kaolinite-chitosan granules was 68.63 and 56.75%, respectively. This controlled release product could be applied in agricultural crop production purpose due to its controlled solubility in the soil, high nutrient use efficiency and potential economic benefits.

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A series of polypropylene (PP) nanocomposites containing 2, 4, and 6 wt % of an organophilic montmorillonite clay was prepared via direct melt mixing in the presence of maleic anhydride grafted polypropylene (PP-g-MAH) as compatibilizing agent. Microstructure characterization was performed by X-ray diffraction analysis. Nanocomposites exhibited a 15 and 22% enhancement in tensile modulus and impact strength, respectively. The heat deflection temperature of PP nanocomposites was 36 C greater than for pure PP. Thermal and mechanical properties of nanocomposites were compared to properties of traditional PP-talc and PP-glass fiber composites. The results showed that the properties of nanocomposites improved compared to ordinary polypropylene composites.

Urea-intercalated kaolinite containing 20 wt% urea was granulated and coated with water-based epoxy resin to prepare nitrogen-based controlled release fertiliser (NCRF). The nitrogen release property was studied using UV-Vis spectroscopy through the diacetylmonoxim colorimetric method for different samples of granules of urea-intercalated kaolinite and nonintercalated urea-kaolinite mixture. Also the effect of granules size and different coating thickness on nitrogen release from coated NCRFs was investigated. The results of release experiments revealed that intercalation of urea into kaolinite caused a three times decrease in the nitrogen release compared to non-intercalated sample. Also, by increasing the size of granules and thickness of coating, the nitrogen release ratio from NCRFs decreased. Finally, a glasshouse trial was conducted to evaluate the effect of coated urea-kaolinite compared with a non-coated one and conventional urea fertiliser granules on rice productivity (Variety MR 219). The yield together with some yield component data (filled spikelet, spikelet per panicle, productive tiller) revealed a highly significant and positive response to coated CRF N fertiliser treatment (one time application). Also, the pooled data of the yield and yield component emphasised that the rice crop responded significantly to treatments involving CRF nitrogen fertilisers as compared to others. The maximum grain yield of 28.73 g/pot belongs to coated CRF, medium grain yield of around 21.74 g/pot from the non-CRF N fertilisers plots and the lowest yield was obtained where conventional urea was applied. The other morphological and physiological characters show a similar trend to the yield.

An electrochemically integrated multi-electrode array has been used for monitoring and visualizing the cathodic disbondment of defective coatings by measuring local electrochemical impedance. Compared with the conventional electrochemical impedance and local current measurement approaches, this new approach significantly enhances the sensitivity of detecting the propagation of coating disbondment by eliminating the effects of the dominating low impedance regions, such as those that arise at coating defects, and thus increases the visibility of higher impedance regions deep in the disbonded coating. Furthermore, it facilitates the probing of electrode processes and mechanisms in selected local electrode regions.

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