Accession Number : ADA117416

Title :   Compressibility of Colloids: I. Compressibility Studies of Aqueous Solutions of Amphiphilic Polymers and Their Adsorbed State on Polystyrne Latex Dispersions by Ultrasonic Velocity Measurements.

Descriptive Note : Technical rept.,


Personal Author(s) : Barrett-Gueltepe,M A ; Gueltepe,M E ; Yeager,E B

PDF Url : ADA117416

Report Date : 01 Jun 1982

Pagination or Media Count : 33

Abstract : Sound velocity measurements were made to obtain compressibility values at 2 MHz, and to investigate the influence of the interface in dispersions of electrostatically stablized dispersions. The measurements were on aqueous dispersions of polystyrene latex as a function of volume concentration up to 49% and temperature up to 80 C (approaching the glass transition temperature), and in solutions of 72.5%, and 78% hydrolyzed polyvinyl alcohol-polyvinyl acetate block copolymers (PVA) as a function of temperature above and below their cloud points. The measurements were extended to latex coated with PVA under conditions known to give a 30 nm layer at room temperature. These dispersions give a resultant compressibility lower than expected from the simple additive effect of the separate components at 25 C and higher. The decrease in compressibility may be due to either or both of two effects: the hydrophobic interaction between the acetate groups and the polymer backbone of the polystyrene latex results in a more rigid structure, and the suppression by the PVA coating of the association-dissociation reaction responsible for the remarkable high adsorption of ultrasound will result in a lower compressibility. (Author)

Descriptors :   *Polymers, *Compressive properties, *Absorption, *Acoustic velocity, *Measurement, Ultrasonic tests, Liquids, Dispersions, Latex, Polystyrene, Rigidity, Solutions(Mixtures)

Subject Categories : Plastics

Distribution Statement : APPROVED FOR PUBLIC RELEASE