Synthesis, characterization and thermal behavior of plasticized poly (vinyl chloride) doped with folic acid-modified...

To inhibit the agglomeration of nanotitanium dioxide, a poly (vinyl chloride) (PVC) composite film doped with folic acid-modified titanium dioxide was synthesized and characterized using X-ray powder diffraction, X-ray photoelectron spectroscopy and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. The average grain size of the folic acid-modified titanium dioxide was found to decrease by 1.3 nm, indicating that the cohesiveness of the nanoparticles is decreased. The lowest temperature for 1.0% thermal decomposition of PVC was determined to be 230.0 °C. The decomposition rate at the peak temperature is found to be 39.6% lower than that of a control sample. The stability of the PVC is improved due to a lower number of surface chlorine atoms as well intermolecular attraction. A mechanism for folic acid modification of titanium dioxide-doped PVC is proposed. After doping, the ester groups in the plasticizer show a significant decrease in the vibration peak intensities observed at 1264 cm^-1, 1736 cm^-1 and 1106 cm^-1. The doped PVC film suppresses the release of CO₂, and the strongest vibration peak at 1264 cm^-1 is found to be 17.2% lower than that for the blank sample, indicating that doping is beneficial for plasticizer recovery.