Local Order and Dynamics of Nanoconstrained Ethylene-Butylene Chain Segments in SEBS

Michele Mauri; George Floudas; Roberto Simonutti

doi:10.3390/polym10060655

Local Order and Dynamics of Nanoconstrained Ethylene-Butylene Chain Segments in SEBS

Polymers (Basel). 2018 Jun 11;10(6):655. doi: 10.3390/polym10060655.

Authors

Michele Mauri¹, George Floudas², Roberto Simonutti³

Affiliations

¹ Department of Materials Science, University of Milano Bicocca, via R. Cozzi 55, 20125 Milan, Italy. michele.mauri@unimib.it.
² Department of Physics, University of Ioannina, 45110 Ioannina, Greece and Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany. gfloudas@uoi.gr.
³ Department of Materials Science, University of Milano Bicocca, via R. Cozzi 55, 20125 Milan, Italy. roberto.simonutti@unimib.it.

Abstract

Subtle alterations in the mid-block of polystyrene-b-poly (ethylene-co-butylene)-b-polystyrene (SEBS) have a significant impact on the mechanical properties of the resulting microphase separated materials. In samples with high butylene content, the ethylene-co-butylene (EB) phase behaves as a rubber, as seen by differential scanning calorimetry (DSC), time domain (TD) and Magic Angle Spinning (MAS) NMR, X-ray scattering at small (SAXS), and wide (WAXS) angles. In samples where the butylene content is lower-but still sufficient to prevent crystallization in bulk EB-the DSC thermogram presents a broad endothermic transition upon heating from 221 to 300 K. TD NMR, supported by WAXS and dielectric spectroscopy measurements, probed the dynamic phenomena of EB during this transition. The results suggest the existence of a rotator phase for the EB block below room temperature, as a result of nanoconfinement.

Keywords: 13C Magic Angle Spinning NMR; 1H Time Domain NMR; X-ray diffraction; block copolymers; dielectric spectroscopy; mesophase; polystyrene-b-poly (ethylene-co-butylene)-b-polystyrene; rotator phase.