(555g) Functional Nanofibers of Associative Polymers Via Electrospinning

Nanofibers of associative polymers have been produced via electrospinning. Associative polymers are unique in their structure, with hydrophobes attached to their hydrophilic backbone, enabling associations between the hydrophobes forming junctions in aqueous solutions. These nanofibers have potential applications in nonwoven surface modification owing to the ability of these polymers to encapsulate hydrophobic moieties. The associative polymer used in this study was a hydrophobically modified alkali-soluble emulsion (HASE). Experiments were conducted using different concentrations of HASE and PEO. We have elucidated process parameters for the electrospinning and determined the effects of solution parameters on the morphology of the resulting nanofibers. Parameters studied include the PEO molecular weight, HASE concentration, ratio between the two polymers in blends, solution conductivity and viscoelasticity. Steady state, as well as dynamic, rheological experiments were performed to correlate the solution viscoelastic behavior with the properties of the resulting nanofibers. SEM micrographs indicate that the solution rheology puts a limit to the HASE concentration which can be electrospun. Our results further suggest that polymer viscoelasticity, in addition to just solution viscosity, substantially influences fiber quality. More importantly, we have been able to achieve significant improvement in the nanofiber morphology by modulating the viscoelastic properties of the polymers using nonionic surfactants generating a new insight into the fundamentals of the electrospinning process.