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

摘要

A novel polyvinylalcohol/silica (PVA/SiO_2) nano-composite is prepared with the self-assembly monolayer (SAM) technique.The SiO_2 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 SiO_2 contents.Using differential scanning calorimetry (DSC),the non-isothermal crystallisation behaviour and kinetics of the PVA/SiO_2 nano-composites are investigated and compared to those of the pure PVA.There are strong dependences of the degree of crystallinity (X_c),peak crystallisation temperature (T_p),half time of crystallisation (t_(1/2)),and Ozawa exponent (m) on the SiO_2 content and cooling rate.The crystallisation activation energy (E) calculated with the Kissinger model is markedly lower when a small amount of SiO_2 is added,then gradually increases and finally becomes higher than that of the pure PVA when there is more than 10% SiO_2 in the composite.