Poly (vinyl chloride) /hydrotalcite (PVC/HT) nanocomposites were prepared through vinyl chloride suspension polymerization in the presence of HT nanoparticles surface modified with alkyl phosphate (AP). The thermal stability, smoke emission and mechanical properties of PVC/HT nanocomposites were investigated. It was found that AP molecules were effectively absorbed by HT particles with no intercalation into the interlayer of HT. The dispersion morphologies of PVC/HT nanocomposites were observed by transmission electron microscopy showing that the majority of HT particles were dispersed in the PVC matrix in the nanoscale. The Congo Red measurement and thermogravimetric analysis showed that the thermal stability time, and the temperatures at 10% weight loss and at the maximum weight loss rate of PVC resins increased as the weight fraction of HT in the composite resins increased. The well-dispersed nano-sized HT showed an obvious smoke suppression effect on PVC. The maximum smoke density decreased about 1/3 and 1/2 when 2.5 wt% and 5.3 wt% nano-sized HT were incorporated into PVC, respectively. Furthermore, PVC/HT nanocomposites exhibited greater tensile strength and impact strength than the pristine PVC.

Acrylate polymer/silica nanocomposite particles were prepared through miniemulsion polymerization by using methyl methacrylate/butyl acrylate mixture containing the well-dispersed nano-sized silica particles coupling treated with 3-(trimethoxysilyl)propyl methacrylate (MPS). The encapsulation efficiency of silica particles was determined through the elution and hydrofluoride acid etching experiments, and the size distribution and the morphology of the composite latex particles were characterized by dynamic light scattering and transmission electron microscopy. The coupling treatment of silica with MPS can improve the encapsulation efficiency of silica and the degree of grafting of polymer onto silica. When 0.10 g MPS/g silica was used to modify silica, the encapsulation efficiency of silica was greater than 95%, and the degree of grafting of acrylate polymer onto silica was about 60%. Although the average size and the size distribution index of the composite latex particles increased as the weight fraction of silica increased, the stable latex containing the guava-like composite particles was obtained. The grafting of polymer onto silica particles improved the dispersion of silica particles in the solvents for acrylate polymer and in the polymer matrix.

The absorption of vinyl chloride (VC) on surface-treated light-grade and nano-scale calcium carbonate (CaCO3), and VC suspension polymerization in the presence of CaCO3 were carried out in a 5 L autoclave. It showed that the absorption of VC on CaCO3 increased with the partial pressure of VC up to a critical point. Nano-scale CaCO3 was more effective in absorbing VC than light-grade CaCO3 at the same temperature and partial pressure of VC due to its greater surface area. The absorption behavior of VC/CaCO3 follows Langmuir isothermal equation. In view of the absorption of VC on CaCO3, Xie s model [J. Appl. Polym. Sci. 34 (1987) 1749] was modified to relate pressure, temperature, the amount of CaCO3 and conversion for VC suspension polymerization in the presence of CaCO3. The model simulation showed that VC conversions at the pressure drop point and at a certain pressure drop decreased with the increase of the amount of added CaCO3, and the influence of nano-scale CaCO3 was greater than that of light-grade CaCO3. The simulated VC conversions fitted well with that obtained from VC suspension polymerizations in the presence of different amounts of light-grade or nano-scale CaCO3.