Chain extender - Thermoplastic polymers, elastomers and additives

By reacting chain extenders with oligomers, it is feasible to obtain polymers of high molecular weight. This method of increasing the size of the polymers is a useful procedure in those occasions in which it is not possible to achieve high conversions during the polycondensation. The Mexcryl chain extender acts as a coupling agent and reacts with the virgin polymer to raise the molecular weight or degraded to restore the original molecular mass as much as possible. The Mexcryl chain extenders is an internal polymer modifier, specifically designed to enhance or maintain the intrinsic viscosity (VI) of transparent polyester resins during processing. The incorporation of the chain extenders to the polyester polymer during extrusion processing will increase the intrinsic viscosity (VI) of the resin. The Mexcryl chain extenders is an active granulated material that can be added directly to the extruder through several measuring devices. The mitigation of the intrinsic viscosity (VI) loss allows producers greater versatility in the supply of raw materials, while making cost reductions, greater efficiency and top quality products. As soon as the extension reaction occurs, two different effects may occur:

In polyester, the Mexcryl chain extender increases the molecular weight through the polycondensation of polymers via reactive processes, involving a greater rigidity of the melt and a better hydrolytic stability. Likewise, the prolonged exposure of the macromolecules at high temperatures (about the melting point) and the use of the low pressures that characterize the last phases of a polycondensation (SSP) are avoided. Chain extenders are compounds capable of reacting with oligomers in a rapid manner, without release of substances of low molecular weight, and at temperatures slightly higher than the melting points of the oligomers and of the polymer. The chain extension process can be carried out during the last stages of obtaining the polymer or also during its processing in an extruder. There are other potential applications of chain extenders, among which we highlight the preparation of block copolymers from mixtures of oligomers, an operation that can be carried out directly in the processing. In this article, a review is made of recent works describing the use of chain extenders with polyamides and polyesters.