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Structural Study on Water‐induced Phase Transitions of Poly(ethylene imine) as Viewed from the Simultaneous Measurements of Wide‐Angle X‐ray Diffractions and DSC Thermograms
Author(s) -
Hashida Tomoko,
Tashiro Kohji
Publication year - 2006
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200651036
Subject(s) - materials science , differential scanning calorimetry , crystallography , phase (matter) , ethylene , polymer chemistry , chemistry , thermodynamics , organic chemistry , physics , catalysis
Thermal behavior of poly(ethylene imine) [PEI] has been studied using simultaneous WAXD/DSC measurement system. PEI exhibits water‐induced and thermally‐induced phase transitions among four kinds of crystalline hydrates: anhydrate (EI/water = 1/0), hemihydrate (1/0.5), sesquihydrate (1/1.5), and dihydrate (1/2). The chain conformation changes from a double helix in the anhydrate to a planar zigzag form in the three hydrates. The anhydrate melts at 60 °C while the hydrates melt differently in the temperature region of 70–110 °C. By means of the simultaneous WAXD/DSC measurements, complex DSC thermograms of PEI hydrates were characterized on the basis of X‐ray diffractions obtained concurrently.