Ionomer studies of polyethylene–acrylic acid copolymer. I. Fiber preparation and properties



Two EAA (Ethylene/acrylic acid) copolymers from Dow Chemical Company have been studied. Primacor resin (5980), having a mol wt of about 30,000 and an acrylic acid content of 19.2%, was converted into 10 and 20 denier per filament fibers to create a high surface area. Cold drawing and use of a fiber lubricant helped prevent sticking and blocking during spinning. The fiber was optimally swollen in a 0.5 N caustic at 55°C to produce an ion exchange fiber. Primacor resin (5980) in pellet form was reacted with alkali and was subsequently hammermilled into an ion exchange porous particulate. Physical and chemical properties, such as thermal properties, swelling, cation exchange activity and selectivity, tensile and elongation properties, among others, were determined on the fiber before and after conversion to specific metal (cationic) forms. The swollen fibers appeared to have more cation binding capacity than hammermilled pellets. The EAA polymers were colored by some metal cations. Some metal cations could be preferentially removed from solutions of mixed cations. Most fibers were weak, even after exchanging with multivalent ions, and did not have a precise melting point. Fiber tension and solution pH during the cationic exchange had an effect on the cation uptake, as well as on the physical properties obtained. © 1993 John Wiley & Sons, Inc.