Epoxy Coatings Physically Cured with Hydroxylcontained Silica Nanospheres and Halloysite nanotubes

Epoxy coatings are usually reinforced by the use of nanofillers, but reactive nanofillers having physical tendency towards epoxide ring opening are preferable. In this work, nanosilica (SiO2) and halloysite nanotubes (HNTs) known for their hydroxylcontained surface are used and their effects on the curing behavior of an epoxy/amine coating is compared. The spherical and tubular nanoparticles used in epoxy led to somewhat different crosslinking. Epoxy/amine systems containing equivalent amount of silica spherical and halloysite nanotube particles were compared for their cure characteristics, i.e. temperatures of starting and ending of curing reaction (TONSET and TENDSET), the exothermal peak temperature (Tp), the temperature range among which curing reaction was completed (∆T= TENDSET TONSET) and the total heat of curing reaction (∆H). Fouriertransform infrared spectrophotometry and scanning electron microscopy analyses were used to assess formation of SiO2. Nonisothermal differential scanning calorimetry was performed at different heating rates and cure characteristics together with values of glass transition temperature of two kinds of systems containing SiO2 and HNTs were calculated, where both nanofillers revealed accelerating role in epoxy curing reaction.