  Scenarios of cosmological evolution having inflationary stages are studied by
using equations of state (EoS) inspired by the quark bag model. A crucial point
is the existence of states where the specific enthalpy of the cosmological
fluid vanishes. A large class of barotropic EoS admits, depending upon initial
conditions, for a concrete equation of state, analogs of the "Big Rip" as well
as solutions describing an exponential inflation followed by the usual matter
dominance. We found scalar field potentials that mimic the behavior of the
cosmological scale factor in case of special EoS from the above class.
Extensions to more general two-parametric EoS are discussed that describe a
pre-inflationary evolution.
