Chain extenders are suitable to increase the molecular weight of semi crystalline polymers; the addition of XIBOND® will result in improved melt strength
Polycondensation polymers like polyesters and polyamides tend to degrade during processing, which results in the loss of molecular weight. This leads to loss of important material properties, especially melt strength. Chain extenders can improve melt strength by connecting chains via a chemical reaction with a polymer’s functional groups – such as the OH, COOH and NH2, for example. This results in a reduced melt flow index (MFI) and increased viscosity.
The addition of XIBOND® chain extenders to thermoplastic polyesters and polyamides leads to branched structures, since chain extenders contain multiple groups that can react with the polymer matrix. The XIBOND® portfolio offers a wide range of maleic anhydride functional polymers that are especially suitable for polyamides. The XIBOND® range also consists of Glycidyl methacrylate (GMA) functional polymers, and the epoxy functionality can react with thermoplastic polyesters. Melt viscosity is increased as a result of the reaction of the functional groups with either carboxylic or amine end groups. In most cases, use of chain extenders leads to an improvement in the overall mechanical properties of the polymer, as well as to observable stabilization in melt flow.
Benefits Chain Extenders
- Improved melt strength
- Optimized processability
- Controllable thickness