Grafting of acrylic acid-co-itaconic acid onto ePTFE and characterization of water uptake by the graft copolymers

Expanded polytetrafluoroethylene, ePTFE, is an attractive material for use as the implant in facial reconstruction surgery because it is bioinert; however, its low surface energy does not facilitate a strong interfacial bond with bone and thus for some applications the surfaces need to be modified to enhance their bone-integration properties. The surface modification of ePTFE membranes with copolymers of acrylic acid (AA) and itaconic acid (IA) using in situ gamma radiation induced grafting has been studied. Solutions with AA mole fractions ranging from 0.4 to 1.0 have been investigated. Graft yields of 35-50% with water uptakes of greater than 300% were obtained using 3 mol L-1 aqueous solutions of the monomers and a total incident dose of 10 kGy. The grafts were characterized by Fourier transform infrared and X-ray photoelectron spectroscopy analyses and the compositional microstructure of the grafted copolymers was investigated. The water uptake by the grafted membranes displayed a complex dependence on polymer chemistry and topology. (C) 2014 Wiley Periodicals, Inc