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Determination of the molecular weight between cross‐links of elastomeric stocks by tensile retraction measurements. II. Polyurethanes
Author(s) -
Hergenrother W. L.
Publication year - 1986
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.1986.070320223
Subject(s) - prepolymer , elastomer , ultimate tensile strength , materials science , swelling , composite material , polyurethane , stoichiometry , tensile testing , polymer , polymer chemistry , chemistry , organic chemistry
Tensile retraction measurements of M c were made on a variety of polyurethanes or polyurethane‐ureas. These samples were prepared using a number of prepolymer MW and functionalities. In addition, the stoichiometry of the cure was allowed to range widely. In all cases, excellent linear correlation coefficients were obtained between the M c and the A max of the test. The slope and M r (the value of M c extrapolated to A max = 1) determined from this was used to characterize the polymer. These data allowed the determination of χ for each of the different systems such that comparable values of M c could be measured by swelling. Identical formulations cured at different temperatures were shown to have measurable differences in M c , slope, and percentage set. These variations appear to relate to the perfection of the network and morphology of the hard domains.