Monoatomic   layers   of  carbon,  known  as
grapheme,     possess    numerous    exceptional
properties.  From the theoretical point of view,
one  of  the  most  interesting  features is the
possibility to use a quasi-relativistic approach
for  description  of  its  properties.  We  will
shortly remind the connection of the Dirac model
with  the  dynamics of electronic excitations in
graphene.  Using  this  model we will derive the
optical   properties  of  grapheme  at  non-zero
temperature,  and  calculate the Casimir effect.
It  will be shown that in high-temperature limit
the  amplitude  of  the  Casimir  interaction of
graphene and an ideal metal tends to one half of
interaction  between  two  ideal  metals. At the
same    time,    for    zero   temperature   the
graphene-metal interaction constitutes only 2.5%
of  the  interaction  between  two  metals. Such
temperature   enhancement   of   the  effect  is
attributed to arising of non-perturbative regime
in graphene.