Synchrotron SAXS studies of segmented polyurethanes

  • B. Chu
  • Y. Li
Part of the Progress in Colloid & Polymer Science book series (PROGCOLLOID, volume 91)


It has been reported by us, for the first time, that segmented polyurethanes (SPUs) based on 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) as the hard segment could form spherulite structures upon melt-quenching to an annealing temperature (T A) above 120°C. Synchrotron small-angle x-ray scattering (SAXS) experiments were performed to investigate the microphase separated structures corresponding to the spherulite formation. With increasing hard-segment content, both the integrated scattered intensity (Q) and the interdomain spacing (d) increased first and then decreased when the hard segment was above 50%, possibly due to phase inversion. With increasing T A, the Q values increased first, reached a maximum at ∼107°C, and then decreased with further increase in T A; the d values showed a monotonic increase. The kinetics of phase separation was investigated after the samples were quenched from the melt to 140°C. Interdomain spacing remained unchanged throughout the whole process. The results indicated that the hard-segment mobility and the system viscosity were the two key factors controlling the phase structure.

Key words

Synchrotron SAXS segmented polyurethanes microphase separation annealing effects phase separation kinetics 


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Copyright information

© Dr. Dietrich Steinkopff Verlag GmbH & Co. KG 1993

Authors and Affiliations

  • B. Chu
    • 1
  • Y. Li
    • 1
  1. 1.Chemistry DepartmentState University of New York at Stony BrookLong IslandUSA

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