Non-isothermal crystallisation kinetics of self-assembled polyvinylalcohol/silica nano-composite

A novel polyvinylalcohol/silica (PVA/SiO2) nano-composite is prepared with the self-assembly monolayer (SAM) technique. The SiO2 nano-particles are homogenously distributed throughout the PVA matrixes as nano-clusters with an average diameter ranged from 15 to 240 nm depending on the SiO2 contents. Using differential scanning calorimetry (DSC), the non-isothermal crystallisation behaviour and kinetics of the PVA/SiO2 nano-composites are investigated and compared to those of the pure PVA. There are strong dependences of the degree of crystallinity (Xc), peak crystallisation temperature (Tp), half time of crystallisation (t1/2), and Ozawa exponent (m) on the SiO2 content and cooling rate. The crystallisation activation energy (E) calculated with the Kissinger model is markedly lower when a small amount of SiO2 is added, then gradually increases and finally becomes higher than that of the pure PVA when there is more than 10% SiO2 in the composite.