Effect of sequence concentrations on segmented polyurethanes properties

Abstract

Purpose

To evaluate in the first stage, the efficiency of changing the nature and the length of diols on the properties of perfectly hard sequences polyurethanes (PU). In the second, the thermal properties of a new series of segmented PU with different concentrations of soft sequences were determined.

Design/methodology/approach

The synthesis of segmented PU has been realised in two stages known as the pre‐polymer method. Various compositions of PU were obtained by keeping the poly(tetramethylene glycol) – PTMG molecular weights constant, but varying its concentration. The products obtained were characterised by IR, NMR, gel permeation chromatography and studied by differential scanning calorimetry.

Findings

The level of phase segregation depends on several parameters, especially the nature of the soft segment and its average molecular weight, nature of the hard sequence and the number of hydrogen bonds established in the PU sequences.

Research limitations/implications

The segmented PU obtained were synthesised from PTMG of number molecular weight 2,000. They could also be synthesised from PTMG of molecular weight 600, 1,000, 2,000, 4,000, etc. The effect of change of PTMG molecular weight on PU properties could also be studied.

Practical implications

Better understanding of the morphology of segmented PU and its effect in the practical domains.

Originality/value

Novel perfectly hard sequences PU have been synthesised and characterised. The effect of soft sequence nature and concentration on the phase segregation in these new series of segmented PU is discussed.

Citation

Elidrissi, A., Krim, O. and Ousslimane, S. (2008), "Effect of sequence concentrations on segmented polyurethanes properties", Pigment & Resin Technology, Vol. 37 No. 2, pp. 73-79. https://doi.org/10.1108/03699420810860419