Thermal Degradation of Poly(vinyl chloride): Effect of Nanoclay and Low Density Polyethylene Content

One of the most serious problems encountered in poly(vinyl chloride) (PVC)processing is due to low thermal stability of the PVC. In this work, the presenceof organoclay and low density polyethylene (LDPE) of variable contents werestudied in relation to the thermal degradation of PVC. The samples were preparedusing an internal mixer with (10, 20 and 30 phr) LDPE and (1, 3, 5 and 7 phr) nanoclayat 180ºC and 45 rpm of rotor speed. The morphology of nanoclay was evaluated byX-ray diffraction and transmission electron microscopy. Thermal degradation wastracked by polyene and carbonyl indices using Fourier transform infrared and thermalgravimetric analysis. The results revealed that exfoliation morphology was obtained at1 and 3 phr concentrations of nanoclay and the intercalation morphology was observedat higher nanoparticle concentration. The addition of LDPE had no significant effect onthe dispersion status of nanoparticles. The lowest polyene and carbonyl indices wererelated to 1 phr concentration of nanoclay. TGA Results showed that the onsettemperature of degradation shifted to higher temperature due to the presence ofnanoparticles and LDPE and the highest shift was attributed to the sample containing1 phr of nanoclay and 10 phr of LDPE. Mechanical properties of the samples showeddirect correlations with nanoclay and LDPE contents and thermal degradation of PVC.The mechanisms for the prevention of thermal degradation reaction of PVC by LDPEand nanoparticle are proposed and discussed.