iscibility and Rheological Properties of Concentrated Solution of Acrylic Copolymer Resins

抄録

Random copolymers of acrylonitrile (AN), vinylchloride (VC) and vinylidenechloride (VD) are dissolved in acetone for a certain range of copolymer composition, though homopolymers of these components are not dissolved. In this study, mechanism of the above phenomenon, which has not been clarified, was investigated from a structural and rheological point of view.
Steady flow and dynamic viscoelastic properties of concentrated acetone solutions of random acrylic resins (AN-VC, AN-VD, AN-VC-VD) were measured by means of a cone-plate type rheometer. Rheological properties and microscopic structure were studied in relation to mole fraction of each component in the copolymers.
A binary AN-VD copolymer of AV/VD=65/35 (in mole fraction) shows a critical gel behavior (i. e. G′~G″~ωⁿ) at 30wt%. On the other hand, the system of AN/VD=55/45 shows still Newtonian flow and flow behavior (i. e. G′~ω², G″~ω¹) at 40 wt%. These phenomena can be elucidated by decreasing of the solubility of the copolymers with increasing AN content.
An AN-VC system of the AN/VC=53/47 forms a gel at 10~15wt%. The systems with high VC content form a thermo-reversible gel in acetone.