  The chemical processes during the Asymptotic Giant Branch (AGB) evolution of
intermediate mass single stars predict most of the observations of the
different populations in Globular Clusters although some important issues still
need to be further clarified. In particular, to reproduce the observed
anticorrelations of Na-O and Al-Mg, chemically enriched gas lost during the AGB
phase of intermediate mass single stars must be mixed with matter with a
pristine chemical composition. The source of this matter is still a matter of
debate. Furthermore, observations reveal that a significant fraction of the
intermediate mass and massive stars are born as components of close binaries.
We will investigate the effects of binaries on the chemical evolution of
Globular Clusters and on the origin of matter with a pristine chemical
composition that is needed for the single star AGB scenario to work. We use a
population synthesis code that accounts for binary physics in order to estimate
the amount and the composition of the matter returned to the interstellar
medium of a population of binaries. We demonstrate that the mass lost by a
significant population of intermediate mass close binaries in combination with
the single star AGB pollution scenario may help to explain the chemical
properties of the different populations of stars in Globular Clusters.

Astrophysics of Galaxies