ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The aqueous solution properties of alkylene oxide polymers and copolymers are related to their interaction with water. In an attempt to better understand this behavior, differential scanning calorimetry has been employed to measure phase changes and water binding in solutions of polyethylene glycol (PEG), polypropylene glycol (PPG), and a 50/50 random copolymer of ethylene oxide and propylene oxide. PEG (Mn = 3510) forms a crystalline eutectic with water at 0.48 weight fraction of polymer. The liquidus curve for water can be fit accurately using the Flory-Huggins expression for solute activity with an interaction parameter of 0.05. PPG and the random copolymer do not crystallize and thus do not form a crystalline eutectic. Based on decreases in the heat of fusion of free water with added polymer, PEG binds more water than the copolymer which binds more water than PPG. The estimated hydration numbers per polymer segment are 1.5 for PPG, 2.3 for the copolymer, and 2.7 for PEG.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1980.070250805
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