Gesso
Modern "acrylic gesso" is a widely used ground that is a combination of calcium carbonate with an acrylic polymer medium latex, a pigment and other chemicals that ensure flexibility, and increase archival life. It is technically not gesso at all and its non-absorbent acrylic polymer base makes it incompatible with media that require traditional gesso such as egg tempera. It is sold premixed for both sizing and priming panels and flexible canvas for painting. While it does contain calcium carbonate (CaCO3) to increase the absorbency of the primer coat, titanium dioxide or "titanium white" is often added as the whitening agent. This allows gesso to remain flexible enough to use on canvas.
Acrylic gesso can be coloured, either commercially by replacing the titanium white with another pigment, such as carbon black, or by the artist directly, with the addition of an acrylic paint. Acrylic gesso can be odorous, due to the presence of ammonia and/or formaldehyde, which are added in small amounts as preservatives. Art supply manufacturers market canvases pre-primed with gesso.
The Painter's Handbook notes a problem with using oil paints over an acrylic gesso ground instead of a traditional oil ground, citing a mismatch in flexibility over time that could cause the oil paint to delaminate.
https://en.wikipedia.org/wiki/Gesso