Anhydrous Poly(2,5-benzimidazole)–Poly(vinylphosphonic Acid) Acid–Base Polymer Blends: a Detailed Solid-State NMR Investigation

Ümit Akbey; Robert Graf; Peter P. Chu; Hans Wolfgang Spiess

doi:10.1071/CH09066

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Anhydrous Poly(2,5-benzimidazole)–Poly(vinylphosphonic Acid) Acid–Base Polymer Blends: a Detailed Solid-State NMR Investigation

Ümit Akbey ^A , Robert Graf ^A , Peter P. Chu ^B and Hans Wolfgang Spiess ^A ^C

+ Author Affiliations

- Author Affiliations

^A Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.

^B Department of Chemistry, National Central University, Taiwan.

^C Corresponding author. Email: spiess@mpip-mainz.mpg.de

Australian Journal of Chemistry 62(8) 848-856 https://doi.org/10.1071/CH09066
Submitted: 2 February 2009 Accepted: 25 March 2009 Published: 13 August 2009

Abstract

The present study aims at understanding the molecular structure and dynamics of the acidic polymer poly(vinylphosphonic acid) (PVPA) blended with the basic polymer poly(2,5-benzimidazole) (ABPBI) under anhydrous conditions. The extent of the acid–base complexation is probed at different mixing ratios. Advanced ¹H, ¹³C, and ³¹P solid-state NMR methods are used to investigate the structural features in these systems. In addition, molecular dynamics is studied by variable-temperature ¹H magic angle spinning and one-dimensional double-quantum NMR methods. Many different types of hydrogen-bonding are identified in the acid–base complexes. Addition of the acidic PVPA to the basic ABPBI changes the molecular packing arrangements of the ABPBI moieties with hydrogen-bond formation as the driving force. The complex with a 1:1 mixing ratio has the lowest activation energy for proton mobility, and at the same time contains the most structured hydrogen-bonded protons. The results show that molecular-level mixing is achieved for the complexes.

Acknowledgements

The authors thank Dr Sivakumar Sekharan and Dr Daniel Sebastiani for their support on quantum chemical calculations of the ABPBI monomer. Financial support is acknowledged from the Bundesministerium für Bildung und Forschung (project DryD under contract no. 0329567).

References

Anhydrous Poly(2,5-benzimidazole)–Poly(vinylphosphonic Acid) Acid–Base Polymer Blends: a Detailed Solid-State NMR Investigation

Abstract

Acknowledgements

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