Partially hydrolyzed poly(methyl methacrylate) (h-PMMA)/Ca(OH)2 composites were synthesized by partially hydrolyzing PMMA in alkaline isopropanol solution followed by precipitating Ca(OH)2 in the solution.Composition and structure of h-PMMA/Ca(OH)2 composites were characterized using X-ray diffraction (XRD)

Fourier-transform infrared (FTIR)

inductively coupled plasma atomic emission spectrometry (ICP) and differential scanning calorimetry (DSC)

and influence of the composites on thermal stability of PVC was studied through Congo red tests

dynamic thermal stability tests and thermogravimetry analysis (TGA).UV-Vis spectra

scanning electron microscopy (SEM) and fusion curves were analyzed to study influence of h-PMMA/Ca(OH)2 composites on transparency and fusion behaviors of rigid PVC compounds.The experimental results showed that h-PMMA chains adsorbed on the surface of growing Ca(OH)2 particles through COO-/Ca2+ bonds decreased the size of the final particles and make a better distribution of Ca(OH)2 in the melt-blended PVC compounds.Compared with traditional stabilizers

the prepared h-PMMA/Ca(OH)2 composites were able to quickly capture catalytic

highly mobile HCl so as to improve thermal stability of PVC compounds during the melt-blending significantly.Furthermore

PVC compounds stabilized with h-PMMA/Ca(OH)2 composites displayed an excellent long-time stability with increasing Ca(Ⅱ) content in h-PMMA/Ca(OH)2 composites.At the same time

the h-PMMA/Ca(OH)2 composites could obviously promote fusion of melt-blended PVC compounds while maintaining their transparency.