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A new criterion of phase separation: The effect of diamine chain extenders on the properties of polyurethaneureas
Author(s) -
Hu Can B.,
Ward Robert S.,
Schneider Nathaniel S.
Publication year - 1982
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.1982.070270627
Subject(s) - crystallinity , prepolymer , materials science , polymer chemistry , diamine , phase (matter) , polymer , glass transition , phase transition , dynamic mechanical analysis , oxide , polyurethane , chemistry , composite material , thermodynamics , organic chemistry , physics , metallurgy
A new criterion of phase separation of segmented polyurethaneureas. is found by comparing the relative crystallinity of the soft segment of polyurethaneurea. This criterion is more sensitive than the conventional thermal transition temperature measurements. The difference of crystallinity can be distinguished even if the thermal transition temperatures are the same. The polymers are synthesized by coupling a prepolymer consisting of poly(tetramethylene oxide) (PTMO) and 4,4′‐diphenylmethane diisocyanate (MDI) with different chain extenders, ethylenediamine (ED), 1.6‐hexanediamine (HD), and 4,4′‐methylenedianiline (MDA). The degree of phase separation is found to relate to the structure of the chain extender and the hard‐segment content as indicated by the relative crystallinity and initial modulus. Several explanations are proposed to discuss the relationship between these factors.