Linear vinyl-terminated poly(diethylsiloxane) chains were synthesized using NaOH and 12-crown-4. Chains of select molecular weights were combined and crosslinked to obtain bimodal
networks. The effects of molecular weight and bimodality on mechanical properties and mesophase formation were studied by comparison with unimodal PDES networks. Mechanical behavior of the
elastomers was studied using a dynamic mechanical analyzer. Both unimodal and bimodal networks exhibited a stress induced amorphous-to-mesophase transition and a discontinuous stress-strain
relationship. Thermomechanical tests indicated that bimodality inhibits the formation of the mesophase in PDES.
Publisher
Cornell Center for Materials Research
Date
2007-08-29
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Additional Notes
Support for the CCMR is provided through the NSF Grant DMR 0520404, part of the NSF MRSEC Program. Additional support is provided by Cornell University, the State of New York, and
by industrial sources.
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