In this work, the effects of the polymer-solvent interaction on the aggrega
tion behavior of polyvinyl chloride (PVC) solutions were studied through el
astic Light scattering and viscosity measurements. The result in Zimm plots
of PVC solutions showed that the second viral coefficient, A(2), value of
PVC/BrBz solutions is higher than that of PVC/DOA solutions at the same tem
perature. The radius of gyration, R-g, in PVC/BrBz solutions is larger than
that in PVC/DOA solutions, indicating that PVC chains in a good solvent Br
Bz must be more extended than those in a poor solvent, DOA. The theta-tempe
ratures are about 32 degrees C and 68 degrees C for PVC/BrBz and PVC/DOA so
lutions, respectively. The result in the temperature dependence of R-g valu
e showed that PVC/BrBz solution exhibits the coil-globule transition, while
no transition is observed in PVC/DOA solution in the measured temperature
range. The chain overlapping concept was used to discuss the heterogeneous
degree of PVC solution. The result showed that PVC/DOA solution is more het
erogeneous than PVC/BrBz solution. The time-resolved light scattering measu
rements indicated that the spinodal decomposition rate of PVC/DOA solution
was faster than that of PVC/BrBz solution. However, the gelation time of PV
C/BrBz solution was shorter than that of PVC/DOA solution. These facts may
imply that the more extended chains in PVC/BrBz solution are advantageous t
o the intermolecular association for the gelation. The scattered profiles (
l(q) vs. q) showed that the scattered intensity of PVC/DOA solution is much
higher than that of PVC/BrBz solution at the same concentration. A scatter
ed maximum was observed in PVC/DOA solution while no other peak appeared in
PVC/BrBz solution. The various aggregation or the gelation behaviors betwe
en PVC/DOA and PVC/BrBz solutions must be concerned with different degrees
of spinodal decomposition in the solution state, which is mainly related to
different degrees of the polymer-solvent interaction. (C) 1999 Elsevier Sc
ience Ltd. All nights reserved.