IMPACT MODIFICATION OF POLYAMIDES WITH LUCOFIN® 1494M –
POSSIBLY IN BLEND WITH LUCOFIN® 1400HN / MN

Commercial polyamides such as PA-6 and PA-66 are generally regarded as tough and ductile materials since they exhibit high tensile elongation to break and high drop weight impact strengths. They become even tougher after equilibration with ambient humidity due to the plasticization effect of the absorbed water.

However, under conditions of low humidities and / or low temperatures due to the lack of plasticizing water and under conditions of stress concentration such as in the presence of sharp notches or cracks, polyamides exhibit brittle failure. This property, commonly evaluated as notched Izod or Charpy impact tests, indicates that unmodified polyamides exhibit relatively low energies for crack propagation.

The impact performance of polyamides can be improved by compounding in modifying elastomeric components, such as Lucofin® 1494M and Lucofin® 1400MN. Lucofin® 1494M is a Maleic anhydride (MAh) grafted variation of Lucofin® 1400MN. Due to the innovative reactive extrusion technology the extremely polar MAh in Lucofin® 1494M is more active than in comparable competition grades and compatibilizes readily with all kinds of polyamides. Commercial impact modified polyamides typically contain 5 % to 25 % of Lucofin® 1494M to maximize the toughening efficiency while retaining a high level of tensile strength and heat deflection temperature. Unreinforced PA as well as glass fibre reinforced PA can be impact modified likewise.

Lucofin® 1494M impact modified PA blends indeed offer a unique combination of high notched Izod impact and drop weight impact strengths, coupled with a good balance of modulus, tensile strength, heat, solvent and abrasion resistance characteristics. These properties are suitable for many engineering and metal replacement applications. In case of cost-driven applications the proportion of Lucofin® 1494M in a PA formulation may be partly substituted by Lucofin ® 1400HN or Lucofin® 1400MN without sacrificing too much impact modification. This procedure is possible because of the polar nature of the non-grafted Lucofin® 1400HN / Lucofin® 1400MN.