Journal Articles

Permanent URI for this collection

https://hdl.handle.net/20.500.14170/316

Browse

Browsing Journal Articles by Author "Alakrach A.M."
  • Publication
    Insight on the structural aspect of ENR-50/TiO2 hybrid in KOH/C3H8O medium revealed by NMR spectroscopy
    ( 2020-01-01)
    Dahham O.S.
    ;
    Rosniza Hamzah
    ;
    Abu Bakar M.
    ;
    Nik Noriman Zulkepli
    ;
    Alakrach A.M.
    ;
    Sam Sung Ting
    ;
    Mohd Firdaus Omar
    ;
    Tijjani Adam
    ;
    Al-rashdi A.A.
    The ring-opening reactions (ROR) of epoxide groups in epoxidized natural rubber/titania (ENR-50/TiO2) hybrid in potassium hydroxide/isopropanol medium were examined using NMR spectroscopy and supported by the FTIR technique. The thermal behaviour of the hybrid was also studied using TG/DTG and DSC analyses. The 1H NMR results suggested that 16.82% of ROR occurred in the hybrid, while the 13C NMR results exhibited five new peaks at δ 19.5, 71.0, 73.7, 91.7 and 94.4 ppm in the hybrid. 2D NMR, such as HMQC, HMBC and COSY techniques, further scrutinized these assignments. The FTIR spectrum exhibited Ti-O-C characteristics via the peak at 1028 cm−1. The TG/DTG results showed four steps of thermal degradation at 44–148, 219–309, 331–489 and 629–810 °C due to the existence of Ti moieties along with a polymer chain mixture (intact and ring-opened epoxide groups) of ENR-50, which in turn led to an increase in the Tg value of the hybrid to 27 °C compared to that of purified ENR-50 at −17.72 °C.
      1