Ultrasonic disassociation of EVA random copolymer in dilute solutions

Ultrasonic disassociation of the ethylene-vinyl acetate (EVA) random copoly mer in 1,2-dichloroethane (DCE), cyclohexane (CYH), and their solvent mixtu res was investigated using viscometry and dynamic laser light scattering (D LLS). It was found that the disassociation of the EVA aggregates in solutio ns 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 dilu te solutions. (C) 2001 John Wiley & Sons, Inc.