We developed a new model based on the lattice cluster theory to describe ph
ase behaviors of binary hyperbranched polymer solution systems. To account
for highly oriented interactions between segments, the proposed model requi
res an additional parameter (delta epsilon/k) related to the energy of the
oriented interaction. A thermo-optical analysis (TOA) technique was used to
determine cloud-points for the given systems. Hyperbranched polyol/water s
ystems exhibit an upper critical solution temperature (UCST) behavior. (C)
1999 Elsevier Science Ltd. All rights reserved.