The role of soft segment molecular weight on microphase separation and dynamics of bulk polymerized polyureas

Alicia M. Castagna, Autchara Pangon, Taeyi Choi, Gregory P. Dillon, James Runt

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The influence of poly(tetramethylene oxide) (PTMO) soft segment length on the phase-separated microstructure, state of hydrogen-bonded associations, and molecular dynamics was investigated in polyureas polymerized from the bulk. For higher PTMO molecular weights (1000 and 650 g/mol) hard segments self-assemble into ribbon-like domains, while incorporation of a 250 g/mol soft segment leads to a predominately mixed segment material. The degree of microphase separation of the hard and soft segments, however, is rather incomplete for polymers synthesized from 1000 and 650 g/mol PTMO and decreases with decreasing soft segment molecular weight. Broadband dielectric relaxation spectroscopy reveals two segmental relaxations: a soft segment rich (α) and slow segmental (α 2) process. When the molecular weight is reduced from 1000 to 650 g/mol the mobility of these processes is reduced, consistent with findings from differential scanning calorimetry and dynamic mechanical analysis.

Original languageEnglish (US)
Pages (from-to)8438-8444
Number of pages7
Issue number20
StatePublished - Oct 23 2012


All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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