Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray scattering (WAXS) investigations of isotactic polypropylene (iPP)vapor-grown carbon nanofiber (VGCNF) composites containing various amounts of VGCNFs ranging between 0 and 20 wt %. are reported. The FTIR investigations were focused on the regularity bands of iPP. The FTIR data indicated a drop in the isotacticity index as the concentration of nanofibers was increased; this suggested a decrease in the crystallinity. WAXS measurements revealed a dominating a1 phase, with a small admixture of ? phase or mesophase. The loading of the polymeric matrix with carbon nanofibers (CNFs) did not induce significant changes in the morphology of the polymeric matrix. A weak decrease in the size of a crystallites upon loading of CNFs was noticed. The experimental data obtained by FTIR spectroscopy supported the WAXS data. Spectroscopic data (a drop in the isotacticity index as estimated by FTIR spectroscopy and the ratio between the crystalline and total areas of WAXS lines assigned to iPP) failed to confirm the enhancement of the degree of crystallinity of polypropylene upon loading by nanofibers. However, whereas both techniques can identify with a high accuracy vibrations in ordered domains (FTIR spectroscopy) and the crystalline structure, including the lattice parameters and the size of crystallites (WAXS), difficulties in the correct assessment of the baseline and of amorphous components may result in important errors (typically >5%) in the estimation of the degree of crystallinity of the polymeric component. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Submitted for the MAR14 Meeting of The American Physical Society On the Glass Transition in Polystyrene-TiO2 Nanocomposites JORGE ALARCON, DORINA M. CHIPARA, KAREN LOZANO, MIRCEA CHIPARA, The University of Texas Pan American, ALIN CRISTIAN CHIPARA, ROBERT VAJTAI, PULICKEL M. AJAYAN, Rice University, THE UNIVERSITY OF TEXAS PAN AMERICAN COLLABORATION, RICE UNIVERSITY COLLABORATION — Nanocomposites of atactic polystyrene (PS) filled with TiO2 nanoparticles of about 15 nm have been prepared. A dilute solution of PS in a good solvent (chlorophorm) has been prepared by stirring the components at room temperature for 24 h at 500 rotations per minute. The solution was then sonicated for 5 minutes by using a high power sonicator. TiO2 nanoparticles were added in the sonicating bath and the sonication continued for 1 hour in order to achieve an uniform dispersion on nanoparticles. Then, a non solvent (distilled water) has been suddenly added under sonication. The sonication continued for about 30 minutes. After 30 minutes, the polymer nanocomposite was isolated from the liquid mixture by filtration. The residual amount of solvent and water was removed by placing the nanocomposites into a vacuum oven at 100 C for 12 hours. The complete removel of water and solvent was confirmed by TGA. The as obtained samples were measured by Differential Scanning Calorimetry and the effect of TiO2 on the glass transition temperature was investigated. The effect of TiO2 on the glass transition of PS is discussed. Mircea Chipara The University of Texas Pan American Date submitted: 15 Nov 2013 Electronic form version 1.4