Studies of phase behavior in blends of PS/PMMA/SAN by using Flory's equation of state theory

Modified Flory's equation of state theory(EOS) was extended to study the ph ase behavior of ternary blends PS/PMMA/SAN containing a copolymer. EOS para meters(the characteristic parameters) for copolymer SAN were evaluated from those for the constituent monomer segments by using proper combining rules , and binary segmental interaction energy density parameters between homopo lymer and copolymer were computed by using simple binary interaction model. The phase behavior of the ternary blend PS/PMMA/SAN was predicted overa wi de temperature range and the calculated Spinodal curves agreed satisfactori ly with the experimental data.