Rheokinetics of a multicomponent epoxy binder modified with polysulfone

Objectives. The work set out to develop epoxy multicomponent binders for polymer composite materials by interrelating the rheological properties and the curing kinetics of the epoxy modified with thermoplastic. Changes in the rheological properties of binders are determined by the competition between two processes: the curing reaction of modified epoxy oligomers with an amine curing agent, and phase separation, which leads to a loss of compatibility between thermosetting components and modifier.

Methods. During the curing process, rotational and oscillational rheometry were used. The kinetic patterns of the curing process of epoxy-amine binders based on a mixture of trifunctional and bifunctional epoxy resins modified with polysulfone were studied.

Results. The dependence of viscosity on curing time of an epoxy binder at various temperatures and polysulfone content was experimentally studied. Gelation and vitrification time, viscosity growth constants, and activation energies values were determined. It was shown that phase separation induced by curing results in the formation of a polysulfone-rich phase. Moreover, the phase separation time decreases with higher modifier content.

Conclusions. It has been established that the adding of polysulfone into the composition of a multicomponent epoxy-amine binder leads to an enhancement in the gelation time by 8–15 min, depending on the curing temperature and the thermoplastic content, which is explained by an increase in the viscosity of the binder.

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