entanglement

A looping (English entanglement ) is a physical cross-linking of two or more polymer chains that this is caused by the crossing. Entanglements keep multiple moving polymer chains, ie, amorphous chains above the glass transition, physically together. Because of this entanglement are significantly weaker than chemical crosslinks and can both by Brownian motion ( reptation, contour length fluctuation (English contour length fluctuation) ) as well as by external force to be solved. Is referred to as disentanglement.

Brownian motions form entanglements again, so this is a dynamic equilibrium. This is described by the statistical average in the molecular weight between two entanglements, the Verschlaufungsmolmasse. This is determined via the so-called plateau modulus, the stiffness of the material in the rubber- elastic plateau in unfilled thermoplastics means, wherein - shear plateau modulus, R - gas constant T - absolute temperature, - density - Verschlaufungsmolmasse. The Verschlaufungsmolmasse is a material constant, which is branching structure, molar mass and molmassenverteilungsunabhängig to a good approximation, however, is increased by large amounts of branching points.