(EN) 31, ABSTRACT POLYMERIC COMPOSITIONS AND METHODS OF EMPLOYING THEM IN PAPERMAKING PROCESSES 5 A POLYMER COMPRISING I) A SYNTHETIC POLYMERIC COMPONEN' THAT HAS BEEN FORMED FROM AN ETHYLENICALLY UNSATURATED WATER-SOLUBLE OR POTENTIALLY WATER-SOLUBLE MONOMER AND AN ETHYLENICALLY UNSATURATED MONOMER CARRYMG A REACTIVE GROUP, V@HEREIN THE 10 REACTIVE GROUP IS DIRECTLY REACTIVE WITH A CELLULOSE BINDING DOMAIN PROTEIN, AND II) A PROTEIN COMPONENT CONSISTING OF A CELLULOSE BINDING DOMAIN PROTEIN, WHEREIN THE CELLULOSE BINDING DOMAIN PROTEIN. THE POLYMER IS PARTICULARLY SUITABLE AS A DRY STRENGTH RESIN IN A PAPER MAKING 15 PROCESS. IT CAN ALSO BE USED AS A V,,E' STRENGTH RESIN, INTERNAL SIZING AGENT OR SURFACE SIZING AGENT.