Article
Structure and Morphology of Segmented Polyurethanes. III. Electron Microscopy and Small Angle X-Ray Scattering Studies of Amorphous Random Segmented Polyurethanes
Polymer
(1986)
Abstract
Transmission electron microscopy and small angle x-ray scattering techniques
are applied to investigate the bulk morphology of compression molded
samples of an amorphous segmented polyurethane system. Samples of different
hard segment content, from 13% to 74% by weight, were synthesized by solution
polymerization, so that the hard segment sequence length distribution of each
sample approximated the most probable distribution. Microscopy results indicate
that meandering cylinders of the soft segment phase are present in the 74%
sample. An alternating plate-like structure is found in the 52% sample.
However, for samples of hard segment content lower than 50%, results from
electron microscopy were inconclusive. The Percus-Yevick hard sphere liquid
theory taking into account the polydispersity of domain size was applied to
calculate the scattering behavior of these lower hard segment content samples
and compared with the experimental data. Modeling results and mechanical behavior
of these samples lead to the conclusion that discrete hard segment domains
of anisotropic shape are present in the soft segment matrix. This conclusion is
also supported by the results from calculations of specific area of domains. A
spectrum of morphologies varying with sample composition is thus obtained for
this particular system of polyurethanes.
Keywords
- Amorphous segmented polyurethane,
- morphology,
- microdomain
Disciplines
Publication Date
1986
Citation Information
William MacKnight, C. H. Y. Chen Tsai, E. L. Thomas and N. S. Schneider. "Structure and Morphology of Segmented Polyurethanes. III. Electron Microscopy and Small Angle X-Ray Scattering Studies of Amorphous Random Segmented Polyurethanes" Polymer Vol. 27 (1986) p. 659 Available at: http://works.bepress.com/william_macknight/249/