Segmented Polyurethane Elastomers with Liquid Crystalline Hard Segments. 3. Infrared Spectroscopic Study

Dynamics of Liquid Crystalline Elastomers

We developed a full non-local model to nematic elastomers in terms of the displacement and the tensor order parameter. We consider both elastic and nematic contributions. This model allows spatial variation of the order parameter field. We also get the dynamics equation using variation principle applied the Lagrangian and the Rayleigh dissipation function. By using small approximation, we get s...

Applications of Liquid Crystalline Elastomers

This chapter focuses on recent developments in the field of liquid crystalline elastomers (LCEs) that bring these materials closer to the world of real applications, concentrating on their actuation properties. First, we briefly introduce different LCE materials that show actuation behavior and explain how they can be synthesized. In the second part, we focus on materials in which a shape chang...

Conformational Analysis of the Crystal Structure for MDI/ BDO Hard Segments of Polyurethane Elastomers

From conformational analysis, we have determined the two lowest energy crystal structures for the hard segments of 4,49-diphenylmethane diisocyanate/1,4butanediol (MDI/BDO)-based polyurethane elastomer. Both crystal forms give prominent X-ray scattering at ;7.6 Å. In one crystal form, (1), there is strong hydrogen bonding between linear chains with a density of 1.30 g/cm, while in the other for...

Specific interactions, structure and properties in segmented polyurethane elastomers

Two sets of segmented polyurethane (PU) elastomers were prepared from 4,4!-methylenebis(phenyl isocyanate) (MDI), 1,4-butanediol (BD) and a polyester or a polyether polyol, respectively. The molecular mass of both polyols was 1000 g/mol. The stoichiometric ratio of isocyanate and hydroxyl groups was 1 and the polyol/total diol ratio changed from 0 to 1 in 0.1 steps. One step bulk polymerization...

New Liquid Crystalline Polyurethane Elastomers Containing Thiazolo [5,4d] Thiazole Moiety: Synthesis and Properties