PHASE-BEHAVIOR OF TELECHELIC POLYISOBUTYLENE (PIB) IN SUBCRITICAL ANDSUPERCRITICAL FLUIDS .1. INTER-ASSOCIATION AND INTRA-ASSOCIATION EFFECTS FOR BLANK, MONOHYDROXY, AND DIHYDROXY PIB(1K) IN ETHANE, PROPANE, DIMETHYL ETHER, CARBON-DIOXIDE, AND CHLORODIFLUOROMETHANE
Cj. Gregg et al., PHASE-BEHAVIOR OF TELECHELIC POLYISOBUTYLENE (PIB) IN SUBCRITICAL ANDSUPERCRITICAL FLUIDS .1. INTER-ASSOCIATION AND INTRA-ASSOCIATION EFFECTS FOR BLANK, MONOHYDROXY, AND DIHYDROXY PIB(1K) IN ETHANE, PROPANE, DIMETHYL ETHER, CARBON-DIOXIDE, AND CHLORODIFLUOROMETHANE, Macromolecules, 27(18), 1994, pp. 4972-4980
The cloud-point pressures for nonfunctional (referred to as blank), mo
nohydroxy, and dihydroxy telechelic polyisobutylene were measured in e
thane, propane, chlorodifluoromethane, dimethyl ether, and carbon diox
ide up to 200 degrees C and 2000 bar. These amorphous polyisobutylene
samples of molecular weight around 1000 are nearly monodisperse and ha
ve zero, one, or two terminal hydroxy groups. In nonpolar solvents, th
e hydroxy groups increase the cloud-point pressures. In polar solvents
, however, one group increases but two groups decrease the cloud-point
pleasures. These shifts in pressures are interpreted on the basis of
intermolecular and intramolecular association estimated from the stati
stical associating fluid theory (SAFT).