Liquid crystal polymer

The term liquid crystal polymer ( LCP ) and liquid crystalline polymer (English liquid crystal polymer LCP ) refers to polymers in the melt ( thermotropic ) or dissolved ( lyotropic ) liquid crystalline properties and thus show a certain degree of order. So that a polymer may have liquid crystalline properties, the mesogens in the polymer must be present. These may be located in both the main-chain and side chains.

The arrangement of the mesogens in the main chain LCP leads to a rod-like molecular shape. Such molecules are not very flexible. This leads to exceptional mechanical and chemical properties. Parallel to the molecular axis have LCP to an extremely high tensile strength and high modulus of elasticity, which predestined main-chain LCP for use as a high-performance fiber (eg, protective clothing, sports equipment, space technology ). In addition, the highly anisotropic geometry ensures a strong intermolecular cohesion, which means that the melting points (if any) are correspondingly high, and a generally poor solubility exists. Therefore, precision components can be (eg, scales, medical equipment ) form, which consider not only the above-mentioned mechanical properties of their shape even in the presence of water or organic solvents.

Side-chain LCP combine the properties of liquid crystals and polymers with flexible backbones. This arrangement results in a fixation of the liquid-crystalline properties of the mesogens, which with the main polymer chain, for example Ester bonds are linked. Thus, a possible flow of conventional liquid crystals, such as liquid crystal displays can be prevented.

Liquid crystalline polymers are also found in nature. How is DNA, just as polyamino acids, such as spider silk, lyotropic phases in water in low concentrations. In addition, can also designate some polysaccharides as LCP.

But are known mainly synthetic LCP such as aramid and Vectran, which are used in ropes and ballistic protection.

This is to main-chain LCP. The first two are, chemically speaking, aromatic polyamides in the Vectra and Vectran is aromatic polyester. Vectran is available as fibrous material, while Vectra is the starting polymer for these fibers.

If you link main chain liquid crystal polymers and side chain polymers with one another, we obtain liquid -crystalline elastomers.

Liquid crystal starting polymers which can then be further processed by means of injection molding or extrusion, are:

  • Sumikasuper LCP from Sumitomo Chemical Industry
  • Vectra LCP from Ticona
  • Xydar LCP Solvay
  • Zenite LCP from Ticona
Solvay (company)
340508
de