(163t) Surface Modification of Deep-Grooved Fibers Using Hydrophilic Migratory Additives

Hydrophilic capillary surface material (CSM) fibers were melt-spun with special designed cross section that provides several deep grooves run along the fiber. Polypropylene (PP) was selected as the base polymer as it has wide use as woven and non-woven fabrics for hygiene, medical, absorbent, and filter applications. In order to create hydrophilic surfaces of the deep-grooved fibers, we proposed the use of migratory additives, i.e., material added to the melt that exhibits controlled migration to the surface of the fiber. Linear, comb-like and hyperbranched additives of various molecular weights and functional group densities were added to PP as surface modifiers. Ciba® IRGASURF HL560, was selected as a reference. We first made PP-additive blend films through solution casting, heat pressing from melt-blended mixtures and film extrusion to evaluate the effectiveness of the additives in generating hydrophilic surfaces. Water contact angles on the film surfaces were measured over time to investigate the additive migration behavior. In particular, films made through melt blending exhibited lower water contact angles than those made through solution casting. Linear polyethylene glycols (PEG) and multi-arm polyethylene oxides (PEO) were found to generate favorable wettability on the PP films, relative to the commercial product when the same weight percentage of additive was used, while hydroxyl-terminated dendritic polyesters were less effective than the other additives. Further study was conducted on lab-synthesized additives including hyperbranched polyglycerol and well-defined comb-like polymers with polyethylene backbones and highly regularly spaced PEO branches. Small quantities of selected additives were melt-spun with PP to make CSM fibers. Capillary wicking of the fibers packed in a transparent tube is conducted with a dye solution to test the wettability.