Viscoelasticity of Aluminium Neutralized Telechelic Poly(ethylene butylene) Ionomer

Abstract

The associative and mechanical properties of aluminium neutralized telechelic poly(ethylene butylene) ionomer, CTPEB-Al, in a nonpolar solvent of decalin were studied from very dilute solution up to the bulk with rheological methods and IR spectroscopy. Dilute solution viscometry revealed that CTPEB-Al molecules are associated in very dilute solution as their smallest associating structural unit made of three CTPEB chains and two aluminium tricarboxylate bonds [(COO − ) 3 Al 3+ : ATC bond]. These smallest associating units are further associated into larger aggregates with increasing polymer concentration C and form viscoelastic networks above C=7 wt%. The viscoelasticity and IR data reveal that in the low concentration range from 7 wt% to 12 wt%, CTPEB-Al chains are associated with each other in such a way that they form pretty long network strands with or without branches as dangling chains that act as elastically effective chains as a whole. In the networks with C ≥ 70 wt%, however, most of the ATC bonds and ion clusters act as effective crosslinking points so that almost 90% chains become elastically effective in the bulk state.