Ionene segmented block copolymers containing imidazolium cations: Structure–property relationships as a function of hard segment content
✍ Scribed by Sharlene R. Williams; David Salas-de la Cruz; Karen I. Winey; Timothy E. Long
- Book ID
- 104087932
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 814 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
Imidazolium ionene segmented block copolymers were synthesized from 1,1 0 -(1,4-butanediyl)bis(imidazole) and 1,12-dibromododecane hard segments and 2000 g/mol PTMO dibromide soft segments. The polymeric structures were confirmed using 1 H NMR spectroscopy, and resonances associated with methylene spacers from 1,12-dibromododecane became more apparent as the hard segment content increased. TGA revealed thermal stabilities !250 C for all imidazolium ionene segmented block copolymers. These ionene segmented block copolymers containing imidazolium cations showed evidence of microphase separation when the hard segment was 6-38 wt%. The thermal transitions found by DSC and DMA analysis found that the T g and T m of the PTMO segments were comparable to PTMO polymers, namely approximately À80 C and 22 C, respectively. In the absence of PTMO soft segments the T g increased to 27 C The crystallinity of the PTMO segments was further evidence of microphase separation and was particularly evident at 6, 9 and 20 wt% hard segment, as indicated in X-ray scattering. The periodicity of the microphase separation was well-defined at 20 and 38 wt% hard segment and found to be approximately 10.5 and 13.0 nm, respectively, for these ionenes wherein the PTMO soft segment is 2000 g/mol. Finally, the 38 and 100 wt% hard segment ionenes exhibited scattering from correlations within the hard segment on a length scale of approximately 2-2.3 nm. These new materials present structure on a variety of length scales and thereby provide various routes to controlling mechanical and transport properties.