Effects of MgAlCe-CO3 Layered Double Hydroxides on the Thermal Stability of PVC Resin

MgAlCe-CO3 layered double hydroxides (LDHs) with different Ce/Al molar ratios were prepared by the constant pH coprecipitation method. The synthesized materials were characterized by XRD and FTIR, and the results showed that the hydrotalcite-like materials have a layered structure. Different LDHs as stabilizers were mixed with PVC resin. The tests of thermal aging and Congo red for the PVC composites were carried out at 180 +/- 1 degrees C, respectively. The results showed when MgAlCe-CO3-LDHs were added into PVC as single thermal stabilizers, 3 phr (parts per hundred PVC resin) MgAlCe-CO3-LDH with Ce/Al (molar ratio) = 0.075 has a better stabilizing effect on PVC than others. Compared with single thermal stabilizers (LDHs or Ca/Zn systems), the composite thermal stabilizers including 0.3 g calcium stearate (Cast(2)), 1 g zinc stearate (Znst(2)), and 3 g MgAlCe-CO3-LDH have significantly enhanced the thermal stability of PVC sample, and the thermal stable time was over 190 min. The main reason could be concluded to the special structure of Ce element and the synergistic reaction among MgAlCe-CO3-LDHs, Cast(2), and Znst(2). (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 2620-2626, 2011