Structural characterization of alpha methyl styrene-butyl acrylate-grafted polyetheretherketone films

Abstract

Radiation-induced graft copolymerization of alpha methyl styrene (AMS)-butyl acrylate (BA) mixture onto poly(etheretherketone) (PEEK) was carried out to develop films of varying copolymer compositions. The characterization of films was carried out with fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The presence of AMS and BA units within the film matrix was confirmed by FTIR. The intensity of the characteristic peaks for AMS and BA increased with the increasing grafted component in the films. The crystallinity of the films as observed from DSC and XRD decreased with the increasing graft levels. On the other hand, the melting temperature of the base polymer was almost unaffected by irradiation and the grafting process. The glass transition temperature (Tg) of the grafted film increased as compared to the virgin PEEK. Ungrafted film showed a stable thermogram up to ∼500°C. However, the grafting introduced a new decomposition range in the copolymer, due to the presence of the AMS/BA. AFM images showed the formation of domains on the grafted PEEK film surface. The SEM also showed domain formation of the grafted component within the PEEK matrix. However, the fracture analysis did not show any prominent phase separation. Mechanical characterization of films in terms of tensile strength, elongation, and modulus was also carried out. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013