Thermosets obtained by reacting highly functionalized maleic anhydride-grafted polyethylene and a polyetherdiamine at several NH2/MA molar ratios were characterized for their gel content, thermal, mechanical, and thermo-mechanical behavior. Gel content varied with composition and a maximum (57%) observed when NH2/MA molar ratio was 1.5. Two melting transitions were observed for thermosets, representing the semicrystalline polyethylene fraction in the gel and sol part of the material in contrast to a single transition for the starting polyethylene. Overall crosslinking suppressed the crystallinity of the polyethylene in the thermoset. A single Tg observed in the DMA analysis suggested phase mixing between the polyethylene and polyether chains. A shift in the Tg observed was related to the degree of crosslinking in the thermosets. Tensile properties of the thermosets were observed to be a strong function of composition and the degree of crosslinking and the optimum mechanical performance was shown by thermosets when NH2/MA molar ratio was 1.5 and 2.0. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012