Positron annihilation and other experimental studies on polycarbonate/MPDMAPP nanocomposite

Abstract

The composite films of polycarbonate (PC) filled with 1‐(4‐methylphenyl)‐3‐(4‐N,N‐dimethylaminophenyl)‐2‐propen‐1‐one (MPDMAPP) were prepared by solution casting. The FT‐IR results of the prepared films confirmed the hydrophobic and dipole‐dipole interaction between PC and MPDMAPP, which is a major driving force for the formation of charge transfer complex (CTC). UV–Vis absorption spectra showed three peaks and the optical band gap Eg for pure PC is 4.31 eV which decreased to 4.1 eV after 15 wt % doping. The fluorescence spectral results show a strong emission and quenching in the wavelength region 510 to 550 nm for 408 nm excitation due to increase in amorphousness, which is observed in X‐ray diffraction (XRD) results. The decrease in ortho‐positronium (o‐Ps) lifetime τ3 and corresponding intensity I3 from positron annihilation lifetime spectroscopy (PALS) and the S‐parameter from Doppler broadening measurements show both inhibition and quenching of Ps formation in the PC/MPDMAPP composite due to the presence of dimethylamino N(CH3)2 group. The mechanical properties such as Young's modulus, tensile strength, and stiffness increase with doping concentration and confirmed that the composite films are mechanically stable. The growth of nanostructures of MPDMAPP within PC films is studied with SEM and TEM images and confirms the uniform dispersion and interaction between the functional groups of PC and MPDMAPP. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42053.