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Investigation of phase behavior and water binding in poly(alkylene oxide) solutions
Author(s) -
Hager S. L.,
Macrury T. B.
Publication year - 1980
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1980.070250805
Subject(s) - copolymer , materials science , polymer chemistry , aqueous solution , differential scanning calorimetry , polypropylene glycol , polymer , ethylene oxide , peg ratio , polyethylene glycol , eutectic system , chemical engineering , phase (matter) , oxide , ethylene glycol , chemistry , thermodynamics , organic chemistry , composite material , microstructure , physics , finance , economics , metallurgy , engineering
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 ( M n = 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.