Ultrasonic disassociation of EVA random copolymer in dilute solutions

Abstract

Ultrasonic disassociation of the ethylene-vinyl acetate (EVA) random copolymer in 1,2-dichloroethane (DCE), cyclohexane (CYH), and their solvent mixtures was investigated using viscometry and dynamic laser light scattering (DLLS). It was found that the disassociation of the EVA aggregates in solutions increases with increasing the time and intensity of ultrasonic shearing and approaches invariant finally. This phenomenon is especially marked for the EVA copolymer with low vinyl acetate (VA) content in the polar solvent of DCE at higher concentration and lower temperature. This is attributed to disassociation of the ethylene segment of the EVA random copolymer in dilute solutions.

Anomalous dilute solution properties of segmented polydimethylsiloxane–polyurea copolymers in isopropyl alcohol

“…Theoretical and experimental results [3,6,7] report positive k H values that lie well within the range of 0 to C1 where the smaller numbers are reported for better solvents. Somewhat larger Huggins' constants of 0.7 or higher are found for polymers in solvents approaching the theta point.…”

“…The well-known example is, of course, use of the intrinsic viscosity to measure average molecular weights via the Mark-Houwink-Kuhn-Sakurada (MHKS) relationship [2]. Among the many applications of dilute solution experiments on polymers appearing in the literature are those to determine average chain dimensions [3], aggregation [4], solvent power of mixed solvents [5], conformational transitions [6], the excluded volume and hydrodynamic effects (e.g. Fox and Flory) [7], polymersolvent interactions [8] and various types of polyelectrolyte behavior [9].…”

Study on chain deformation of polyacrylamides in solutions and its flocculation performance during the flocculation process

“…The values of [η] of samples as well as their polymerization conditions are listed in Table I. However, the other [η] of the PAAm at different external experimental conditions such as, added salt and pH of the solution were determined by the single point method with the equation,22 where the η r is the relative viscosity at a given solution concentration C . …”

Ultrasonic treatment of polyacrylic acid sodium/NaA zeolite hybrid membranes for the pervaporation dehydration of ethanol

“…Various techniques exist for the dispersion of particle agglomerates, such as the application of high shear forces during mechanical stirring and the direct incorporation by chemical methods . Another suitable alternative technique for the dispersion of nanoparticles is ultrasonication . For instance, Boukerrou et al successfully incorporated titanium dioxide nanoparticles into epoxy resin via the ultrasonic process.…”

“…Jun et al found that the dispersion and adhesion of B 4 C particles in epoxy resin can be enhanced by using direct ultrasonic excitation. Meanwhile numerous studies have shown that ultrasonication has an impact on the structure and crystalline order of a polymer . These studies have shown that ultrasonic treatment can degrade polymer chains.…”