Mechanism on smoke suppression of PVC/nano hydrotalcite-zinc oxide composite

PVC/nano hydrotalcite (HT)-zinc oxide (ZnO) composite were prepared to reduce the smoke release of rigid poly (vinyl chloride) (PVC) as it's burning. Thermal stabilities of the modified PVC and decomposed products were investigated by means of thermogravimetry and prolysis-gas chromatography-mass spectrum (Py-GC-MS). As a result, HT-ZnO obviously accelerated decomposition of PVC to release hydrogen chloride, and the decomposed PVC consequently produced the trans-conjugated polyene sequences, which easily formed cross-linked structures. However, a cyclization reaction in PVC chain without the additives produced aromatic compounds such as benzene and naphthalene at 400 °C Even though the amount of aromatic compounds was released from the PVC modified with HT-ZnO at the temperature of 600°Q the content of the decomposed products is relatively lower, comparing with unmodified PVC.