Effect of filler on kinetic characteristics of glass transition in polymer composite materials

Dynamic mechanical spectroscopy and differential scanning calorimetry were used to study the effect of various fillers (carbon fiber, glass fiber, and aramid fiber) on the kinetic characteristics of glass transition in polymer composite materials based on epoxy resin. It is shown that the composite based on carbon fiber is the most fragile among the materials studied, whereas the polymer composite material based on aramid fiber exhibits the lowest rate of variation of the relaxation time above the glass-transition temperature. A relationship is determined between the heat conductivity and fragility of polymer composite materials. The effect of various fillers on the curing kinetics of the epoxy matrix upon glass transition is prognosticated, with the difference in the degree of curing reaching a value of 4–5%. The strongest filler effect on the curing kinetics is observed in the chemically controlled region, which may be due to the catalytic effect of functional groups on the fiber surface.