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The manipulation of the physical characteristics of nonwovens and paper by variation of fiber and web geometry is briefly reviewed in terms of a new system of bonding in which the adhesive interfiber forces are a consequence of ionic chemical bonds. These bonds were created by the sequential covalent introduction of anionic sites onto the interior and exterior surfaces of microporous pulp and rayon fibers using a chloro-s-triazinyl fiber reactive dye and subsequent stoichiometric reaction with crosslinking polycations derived from ethylenimine. The tensile properties of both the pulp and rayon fiber assemblages were significantly augmented as a result of the development of both ionic inter- and intra-fiber bonds.

CATIONIC polymers are strongly adsorbed onto cellulose fibres by mechanisms which are regarded as primarily electrostatic1–5. Unexpectedly, however, the adsorption of polyethyleneimine (PEI) is apparently not completely reversible and this has been attributed to an intimate chain entanglement with polysaccharide molecules which inhibits its elution4,6. We now present evidence for a new general type of physical combination of polymers with microporous solids which is responsible for this apparent irreversible retention of PEI.