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°C, the content of the decomposed products is relatively lower, comparing with unmodified PVC.