Design, development and performance evaluation of PDMS based antifoaming emulsions for leather production

Leather production is a process where emulsion and dispersion based applications are used intensively by using surface active agents. Macro and micro foams turned out in some physicochemical practices causes various problems based on use of surface active agents in aqueous medium. Macro foams are large air bubbles that are stabilized by surfactants in the system. On the other hand, micro foams are mainly small bubbles that are transported into the system. These formations are undesirable in aqueous applications since they cause quality problems in finished product. They also give rise to increase ecological problems in production. Particularly, intensive agitation of various surfactant-based additives used during leather beamhouse processes encourages profound foaming and it becomes necessary to overcome this problem in terms of high quality production. In this thesis, the newly developed prototypes which were prepared with different variables affecting the design of antifoaming emulsions will be reconsidered. In additionally, the parameters of these complex emulsification and their characteristics influencing the knock down ability of antifoaming agents will be reviewed. Some experiments were carried out with different parameters in terms of emulsion characteristics and performance, then, results were evaluated comparatively. According to the results, the emulsion prepared using a dispersion containing 6.5 % solid particles and 350 cSt PDMS oil, emulsified with a 7 % emulsifier was found to give the best results in terms of antifoaming performance. It was observed that emulsion prepared using dispersion containing 1000 cSt and 5000 cSt PDMS oil had the highest phase inversion temperature. As a result, the use of antifoaming emulsions in leather production may reduce the negative effects of foam based problems and contribute to environmentally sustainable production by minimizing the chemical wastes.