Poly(vinyl chloride)/layered double hydroxide (PVC/LDH) nanocomposite has been prepared via solution intercalation process using dodecyl sulfate (DS-) or stearate anion modified LDH. XRD and TEM results give evidence that the inorganic LDH particles were dramatically exfoliated into nanoscale and homogeneously dispersed in PVC matrix. The enhanced thermal stability was confirmed by conventional Congo Red test. The nanocomposite containing Mg3Al-LDH-stearate had the maximum of increased dehydrochlorination time, 15 times of that of neat PVC, and more than twice of that of PVC/LDH-NO3 composite and PVC/LDH-DS nanocomposite at 5 wt% loading. Furthermore, its thermal stability time increased with the LDH content. At 10 wt% loading of Mg3Al-LDH-stearate, it reached 20 times of that of PVC, and obviously larger than that of the previously reported nanocomposite using alkyl phosphonate (AP) grafted LDH. The reason may lie on the absorption of the released HCl during degradation by both nanoscale dispersed LDH particles and stearate anions. (C) 2008 Elsevier Ltd. All rights reserved.