Compatibility and thermal decomposition behavior of acrylic block copolymer modified epoxy resin

Abstract

A series of epoxy modified with acrylic amphiphilic block copolymer (BCP) were prepared with different BCP contents. The compatibility between BCP and epoxy matrix was characterized by differential scanning calorimetry (DSC). The nanostructures in the thermosets were investigated by means of atomic force microscopy (AFM). The thermal stability and degradation kinetics of BCP/epoxy blends were investigated that by thermogravimetric analysis (TGA) in N2 atmosphere. The ‘model free method (Vyazovkin’ method) and ‘model fitting’ methods (Coats-Redfern method, Malek method and ABS differential method) were applied to analyze the decomposition of cured neat epoxy and BCP/epoxy blends. The glass transition temperature (Tg) of the BCP/epoxy blends was found almost not affected by the incorporation of BCP. The miscibility of acrylic BCP in the epoxy matrix was verified by comparing the theoretical calculation with experimental results. AFM further confirmed the good miscibility of the blends. The thermal stability of the BCP/epoxy blends remained unchanged and the main decompose reaction was slightly accelerated from the perspective of transition state theory. The relationship between pre-exponential factor and reaction activation energy was established by utilizing the kinetic compensation parameter method. The degradation kinetics of both neat epoxy and BCP/epoxy blend were found abide to the Fn (n > 3/2) reaction mechanism.