Abstract:
The hybrid material of natural rubber coated with silica and titania, respectively, was prepared to obtain an antibacterial property. The optimum condition for powdery rubber synthesis by spray-drying of natural rubber (NR) compound latex was investigated in order to produce non-sticky NR particles with a high yield percentage, using 24 factorial experimental design The studied parameters or effects in this study were nozzle flow rate (500-700 L/h), inlet air temperature (100-150 ºC), SDS content (35-55 phr) and mass flow rate of dry rubber (1.2-1.7 g/min), giving the maximum yield of 59.72%. Next, the duration time of silica coating, using tetraethoxysilane (TEOS) as the precursor by chemical vapor deposition (CVD) at 60 ºC, was varied between 4-48 hours. The deposition time of 8 hours was selected because the particles did not shown dense agglomeration and they had a relatively high silica content of 3.6%. Next, the particles were coated with titania using ammonium hexafluorotitanate ((NH4)2TiF6) by liquid phase deposition (LPD) at 60 ºC. The deposition time was varied between 4-9 hours. The deposition time of 6.5 hours yielded particles without dense agglomeration, according to SEM micrographs, and the particles had the titania content of 0.75%. The titania coating did cause a loss in elasticity. In addition, the antibacteria results based on ASTM E2149-10 showed 99.99% reduction of Escherichia coli and Staphylococcus aureus as the hybrid particles were in contact with the bacteria under the exposure of fluorescent light for 20 minutes, up to 3 repetitions.