Effect of Polyhedral Oligomeric Silsesquioxanes Nanoparticles on Thermal and Mechanical Properties of Poly(vinyl chloride) Composite Materials

The modification of poly(vinyl chloride) (PVC) by polyhedral silsesquioxane containing both methacryl and octyl groups (MeOctPOSS) was the task of studies. The PVC nanocomposites with MeOctPOSS concentration between 1 and 10 wt% were prepared by melt mixing processing, and the homogeneity of MeOctPOSS dispersion in the polymeric matrix was confirmed by scanning electron microscopy and energy dispersive spectroscopy observations. The influence of MeOctPOSS on glass transition temperature (T_g) determined by means of dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) was observed, whereas, higher the measurement frequency, higher the glass transition temperature was noted. The MeOctPOSS concentration‐dependent PVC glass transition temperature was shifted from 73.8°C to about 68°C (? = 1 Hz) and from 76.5°C to 70.8°C (? = 10 Hz) for increasing additive content. Similar result of decreasing T_g value was observed by DSC method. An introduction of 10 wt% of MeOctPOSS into the PVC matrix results in a visible decrease of the maximum value of loss modulus (G′) of approximately 12% and 18% by 1 Hz and 10 Hz, respectively, as well as in a significant reduction of the static elastic modulus. It was stated that the polyhedral oligomeric silsesquioxanes with both methacryl and octyl groups may act as plasticizers of the PVC matrix. J. VINYL ADDIT. TECHNOL., 25:E48–E54, 2019. © 2018 Society of Plastics Engineers