Abstract: Liquid hydroxyl-terminated polybutadiene (HTBS) was employed to modify epoxy (EP) at presence of benzyldimethylamine to improve the brittleness and resistivity of epoxy. This paper investigated the thermal stability, morphology, mechanical, and electrical properties of HTBS modified EP. The formation of chemical bond between terminal hydroxyl group of HTBS and epoxy group of EP, enhanced the compatibility between the two materials. The use of HTBS decreased the thermal stability of EP. At low HTBS concentration the bending, tensile, and impact strengths of EP are enhanced obviously. SEM micrographs verified the phase separation, accountable for improved toughness of modified epoxy. Additionally, the HTBS/EP exhibited clear improvements in electrical insulations and dielectric properties, i.e., low dielectric permittivity and dissipation factor as compared with the unmodified one.

Key words: epoxy resin, hydroxyl-terminated polybutadiene, toughening, dielectric permittivity