A crossbridging agent is a difuntional molecule that, through a chemical reaction, joins polymeric materials together that are on opposite sides of an interface. Unlike crosslinking, crossbridging does not join two polymer chains to form a single continuous piece of rubber during the vulcanization process. Rather, the rubber remains distinct, separated by an interface; however, a strong covalent or ionic bond is typically created.
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Crossbridging Wikipedia(Text) CC BY-SA