Magnesium Oxide MgO is used in the Rubber and Plastic applications as an acid scavenger, scorch retarder or curing agent during the cross linking of several rubber compounds containing halogens or nitrile groups. Also used as a thickening agent for sheet and bulk molding compounds, as a hardening agent during phenolic resin curing, and as raw material for hydrotalcites to be used as acid scavenging additives in PVC and polyolefins.