Preparation of high-activity antifoaming silicone agents
Polimery 1997, No 11-12, 702
Reasons for foams and requirements for antifoaming agents are described. An original route to prepare polydimethylphenylsiloxanes (PDMS) involves hydrolytic copolycondensation of dimethyldichlorosilane (DDS) with phenyltrichlorosilane (FTS). Foam breakability values (Z) were established and compared in the 12 PDMS prepared at varying DDS/FTS initial mole ratios, in their mixtures with cyclic methylsiloxanes (D4 and D5), and in commercial polydimethylsiloxanes. The Z-value was found to be related to agent's surface tension and spreadability. Unlike polydimethylsiloxanes, several PDMS prepared in a "pure” condition were found to be high active foam breakers.