The NEXAMITE® product range for melt strength and viscosity modification of polyamides is divided into two categories; linear chain extenders and long chain branching agents. NEXAMITE A94 and A99 are linear chain extenders and provide increased molecular weight during the melt processing of the polyamide. This effect can be advantageously employed in, e.g. extrusion applications of filaments, where process stabilization and increased mechanical properties can be realized. NEXAMITE A56 and A93 act as long-chain branching agents which make them useful for, e.g. blow-molding and extrusion applications. Unwanted effects, e.g. parison sag, can be avoided and long chain branching also yields increased flexural strength and modulus with retained or increased elongation at break.
NEXAMITE A32 and A33 can be used as cross-linkers for polyamides. NEXAMITE A32 can be used alone for low molecular weight resins while it is recommended to use a combination of A32 and A33 for medium and high molecular weight resins. Addition of these products to polyamide has little or no negative effect on processability during compounding and injection molding. Effects achieved using NEXAMITE A32/A33 include increased long term heat stability >180°C, reduced moisture uptake and increased tensile strength and modulus at temperatures >Tg. NEXAMITE A32/A33 modified resins can, when combined with a post processing heat treatment stage, be used as an alternative to radiation cross-linked polyamides.