Study regarding mechanical, thermal and structural properties of some elastomeric polyamide blends destined to cable insulating

This research is the main part of a detailed study concerning the preparation of cable insulation having improved mechanical, thermal and structural performances. The paper presents the various PA6-based blends with some differently structured elastomers belonging to the polymer class of ethylene-propylene diene rubbers: EPDM (ethylene-propylene-diene terpolymer), Exxelor (medium viscosity semi-crystalline ethylene copolymer functionalized with maleic anhydride), Lotader (random terpolymer of ethylene, ethyl acrylate and maleic anhydride), Marfran (mixture polypropylene, polyethylene and polyethylene vinyl acetate) and SEBS (styrene-ethylene/butyl-styrene block copolymer). The blending proportions covers the following PA6/elastomer ratios: 100/0, 90/10, 80/20 for EPDM, 100/0, 95/5, 90/10 and 80/20 for formulations including rubber components Exxelor, Lotader, Marfran. The characterisation of material functional features was performed as tensile and bending mechanical tests, three-point bending strength, thermal endurance tests and X-ray analysis determinations were achieved on these compositions. The results develop the different contribution degrees of each elastomer in connection with their molecular structures. From mechanical tests it was found that the best option is compounded PA6 + 5% Lotader. The accomplished thermal tests reveal significant variations in the material microstructures. The addition of this elastomer in increased concentrations leads to a higher crystallinity degree of the compound.