Phase separation is the foundation of aqueous two-phase polymerization.The polymerization process cannot proceed normally without phase separation.Phase separation is regarded as the result of superposition of various factors.Ammonium sulfate (AS) concentration is one of these factors and increasing AS concentration is obviously beneficial to phase separation.If the change of some other factor can reduce the amount of AS needed to achieve phase separation

this change is in favor of phase separation.In this paper

the amount of AS for phase separation was used as the standard to evaluate the effects of various factors on phase separation

and the lower AS amount the better.The amounts of AS for phase separation of AS-water-polyacrylamide (PAM)

AS-water-CPAM aqueous two-phase systems were measured.The experiment results showed that adding some special material (such as liquid paraffin

cyclehexane

n-hexane

or t-butanol

PEG200 in the case of plentiful existence of monomer)

lowering temperature

and increasing PAM concentration were beneficial to phase separation.But plentiful existence of monomer could significantly decrease polarity of AS solution

which was the most important factor affecting phase separation.