Liquid Crystalline Polyurethanes Studied by Positron Annihilation Method

• Authors: A. Baranowski , M. Dębowska , A. Jankowski , K. Jerie , P. Penczek , J. Rudzińska-Girulska , B. Szczepaniak , A. Wolińska-Grabczyk
• Languages of publication: EN

Abstracts

EN

A series of liquid crystalline polyurethanes of different both flexible spacer length and mesogenic group content was studied by means of positron annihilation method. The investigated polymers were targeted on the sep­aration of aromatic hydrocarbons from their mixtures with aliphatic ones. The effect of modification of the liquid crystalline polyurethane chain on the polyurethane free volume size and free volume distribution was determined on the basis of the positron annihilation lifetime spectra. In the positron annihilation lifetime spectra measured for the samples under study two long com­ponents of several nanoseconds, characteristic of o-Ps decaying by pick-off, occurred. The correlation of the values of the o-Ps lifetime with the size of the free volume region allowed to recover the free volume distributions with the use of the method employing the numerical Laplace inversion technique. The obtained results were compared with the diffusion data on the mobility of liquid hydrocarbons in the liquid crystalline polyurethanes enabling the correlations between polymer structure and its transport properties to be evaluated.

Keywords

EN

71.60.+z; 81.20.Sh; 78.70.Bj; 82.30.Hk

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 1995
• Volume: 88
• Issue: 1
• Pages: 21-27

Dates

published

1995-07

Contributors

author

A. Baranowski

• Institute of Experimental Physics, University of Wrocław, Maxa Borna 9, 50-204 Wrocław, Poland

author

M. Dębowska

• Institute of Experimental Physics, University of Wrocław, Maxa Borna 9, 50-204 Wrocław, Poland

author

A. Jankowski

• Institute of Coal Chemistry PAN, Sowińskiego 5, 44-101 Gliwice, Poland

author

K. Jerie

• Institute of Experimental Physics, University of Wrocław, Maxa Borna 9, 50-204 Wrocław, Poland

author

P. Penczek

• Industrial Chemistry Research Institute, Rydygiera 8, 01-793 Warszawa, Poland

author

J. Rudzińska-Girulska

• Industrial Chemistry Research Institute, Rydygiera 8, 01-793 Warszawa, Poland

author

B. Szczepaniak

• Industrial Chemistry Research Institute, Rydygiera 8, 01-793 Warszawa, Poland

author

A. Wolińska-Grabczyk

• Institute of Coal Chemistry PAN, Sowińskiego 5, 44-101 Gliwice, Poland