scholarly journals Lower Critical Solution Temperature Phase Behavior of Natural Rubber/Polybutadiene Blend

2002 ◽  
Vol 34 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Seiichi Kawahara ◽  
Yasuhiro Asada ◽  
Yoshinobu Isono ◽  
Kiyoshige Muraoka ◽  
Yasuhisa Minagawa
Keyword(s):  
Natural Rubber ◽  
Phase Behavior ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Temperature Phase ◽  
Critical Solution Temperature

scholarly journals Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4850
Author(s):  
Brian R. Carrick ◽  
Claire L. Seitzinger ◽  
Timothy P. Lodge
Keyword(s):  
Ionic Liquid ◽  
Phase Behavior ◽  
Lower Critical Solution Temperature ◽  
Second Virial Coefficient ◽  
Coexistence Curve ◽  
Solution Temperature ◽  
Temperature Phase ◽  
Strong Concentration ◽  
Critical Solution Temperature ◽  
Heating And Cooling

Polymer/ionic liquid systems are being increasingly explored, yet those exhibiting lower critical solution temperature (LCST) phase behavior remain poorly understood. Poly(benzyl methacrylate) in certain ionic liquids constitute unusual LCST systems, in that the second virial coefficient (A2) in dilute solutions has recently been shown to be positive, indicative of good solvent behavior, even above phase separation temperatures, where A2 < 0 is expected. In this work, we describe the LCST phase behavior of poly(benzyl methacrylate) in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide for three different molecular weights (32, 63, and 76 kg/mol) in concentrated solutions (5–40% by weight). Turbidimetry measurements reveal a strong concentration dependence to the phase boundaries, yet the molecular weight is shown to have no influence. The critical compositions of these systems are not accessed, and must therefore lie above 40 wt% polymer, far from the values (ca. 10%) anticipated by Flory-Huggins theory. The proximity of the experimental cloud point to the coexistence curve (binodal) and the thermo-reversibility of the phase transitions, are also confirmed at various heating and cooling rates.

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