Einflusse auf die Partikelgrosse,Stabilitat und Hydrolyse von ASA-Emulsionen

摘要

Control of particle size,stability and hydrolysis of ASA emulsions This work has shown that a reproducible ASA emulsification with optimal particle size is possible,and well controllable,in the laboratory.The most important factors for the adjustment of particle size are emulsification time,shear forces,ASA concentration and temperature.The protection colloid and the emulsifierused are also an important factor for the particle size that can be achieved.Concerning the emulsification there is an optimum as regards particle size-which is mainly dependent on the starch to ASA ratio and the viscosity of the starch.The stability and hydrolysis of ASA emulsions depend mainly on pH,temperature and water hardness(Ca~(2+),Mg~(2+)).However,the tendency to build up agglomerates and deposits is only caused by calcium ions,due to the fact that the ASAcid calcium salts have a much higher tack than the magnesium salts.Agglomeration and hydrolysis can be reduced by increased starch addition or by the introduction of long-chain polymers such as Polyacrylamides.It is surprising that the cationic Charge of the used protection colloid shows almost no influence on the emulsion and hydrolysis stability of the ASA.Furthermore,particle size plays an important role during the evaluation of hydrolytic stability and deposition.Therefore it is very important that emulsions and different protection colloids should only be compared at the same particle size.However,high cationic liquid starches seem to be the best alternative Solution,as compared to the Standard cocking starches.