Imre, A. R., Melnichenko, G., Van Hook, W. A. and Wolf, B. A.

"On the effect of pressure on the phase separation of polymer blends and polymer solutions: oligostrene/n-alkane systems"

*Phys. Chem. Chem. Phys.*
**2001**,
*3*,
1063-1066.

**Abstract: **Critical temperatures of some binary solutions
of weakly interacting low molecular weight polystyrenes dissolved in linear
alkanes (oligoethylenes) were measured over the range of 0.1 to 100 MPa. While
(d*T*/d*P*)crit along the upper critical solution (UCS) locus
for a "typical blend" is possitive, and for the "typical solution"
can either be possitive or negative (but is usually negative), there is no essential
difference between blend and solution. Rather, the difference in sign is a consequence
of the location of the hypercritical point (that point in (*T*,*P*)crit
space where (d*T*/d*P*)crit changes sign, [(d*T*/d*P*)crit
= and (d2*T*/d*P*2)crit >0], also called the double critical
point, DCP), which normally found at *P* > 0 for solutions but is shifted
to *P* < 0 for blends.

preprint number: 215