Tailoring thermal and flame retardant properties via synergistic effect in polyvinyl alcohol nanocomposites based on polyphosphonate and/or SiO2 nanoparticles

New polymer nanocomposites with improved fire performance were developed based on polyvinyl alcohol (PVA) as polymer matrix, a polyphosphonate (PPH) and/or SiO2 nanoparticles. The structural and morphological properties of the resulting nanocomposites were investigated by Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, Scanning Electron Microscopy (SEM) and contact angle measurements. Thermal and combustion properties of the nanocomposites were determined by running thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and microscale combustion calorimetry (MCC) tests. The introduction of PPH and SiO2 nanoparticles increased the contact angle values, the glass transition temperature and the char yield at 800 °C. MCC tests revealed substantial improvement on the fire-resistant properties of the samples containing both PPH and SiO2, due to the synergistic effect. The total heat release decreased from 20.75 kJ/g, in pure PVA to 17.69 kJ/g in the sample containing 10% SiO2 and 10% PPH.