reacted further for example by hydrolyzing the epoxide or reacting the halide or epoxide with a nucleophile an example of a capping group for polyguanidine polymers or copolymers is represented by structural formula xxxiv where r 11 is a c2 c90 alkyl c2 c90 oxyalkyl or aromatic group and the symbol u201c u201d represents the bond connecting the cap to the polymer or copolymer ionene polymers of the invention may also be cross linked with primary secondary or other polyfunctional amines using means known in the art ionene polymers can be cross linked by polymerizing in the presence of a multivalent nucleophile i e a compound with three or more nucleophilic groups such as a triamine or tetraamine or a multivalent electrophile i e a compound with three or more nucleophilic groups such as a trihalide or tetrahalide the invention will now be further and specifically described by the following non limiting examples hexamethylenebiscyanoguanidine 3 99 mmoles 1 00 g and 4 9 dioxa 1 12 dodecanediamine 3 99 mmoles 0 848 ml were added to a 40 ml vial with a septa cap followed by 2 equivalents of concentrated hcl the mixture was heated to 135 145 u00b0 c in a shaker overnight the resulting clear yellow brittle solid was dissolved in water and purified by centrifugation through a 3k macrosep filtration membrane 4 4 u2032 trimethylenebis 1 methylpiperidine alt 1 8 dibromooctane was prepared by dissolving 4 4 u2032 trimethylenebis 1 methylpiperidine 39 9 ml in 30 ml of dmf in a 250 ml erlenmeyer flask.