Abstract:
To study the effect of agitation speed (100-500 rpm) on the properties of acrylic styrene copolymer emulsion in semibatch emulsion polymerisation reactors. Changes in properties of both polymer emulsions and dried films were observed. Within the range of agitation speeds employed, it was found that there were optimal speeds in between 150 and 350 rpm at which the emulsion becomes transparent. Besides, the operation at these optimal speeds gave small particle size (average particle size 0.12-0.14 micron) with narrow size distribution, low coagulum formation (0-0.02%), high viscosity (1,103-1,410 centipoise), high non-volatile matter (50.11-50.69%) and surface tension between 47.25-47.55 dyne/cm respectively. Nevertheless, in case of dried films obtained therefrom the film properties were found to be dependent on the agitation speed in the same manner as the emulsion with the exception only for glass transition temperature which was found to increase (in the range of 28.5-35.3 celsius degree) with the increase of speed used in preparing the emulsion. At the optimal speed (150 to 300 rpm) the minimum film forming temperature were low (25.3-27.0 celsius degree) and light transmission were high (99.0-99.6%)