The chemical used in DPC (Damp Proof Course) injection cream, according to the provided reference, is a Silane/Siloxane base.
In more detail:
DPC injection creams are designed to create a water-resistant barrier within walls to prevent rising damp. The Silane/Siloxane base acts as the carrier for the active ingredient, enabling deep penetration into the building material. This deep penetration is crucial for effective damp proofing. Silanes and siloxanes react with the masonry to form a water repellent resin within the wall, therefore preventing the capillary rise of water.