Non-isothermal crystallization kinetics and nucleation activity of filler in polypropylene/microcrystalline cellulose composites

The non-isothermal crystallization kinetics of isotactic polypropylene (PP) and iPP/microcrystalline cellulose 1 (MCC1) (hydrolyzed by HCl) and iPP/microcrystalline cellulose 2 (MCC2) (hydrolyzed by H2SO4) composites were investigated by differential scanning calorimetry techniqye (DSC) with various cooling rates. The Avrami, Ozawa, and Mo equations were applied to describe the non-isothermal crystallization kinetics and to determine the crystallization parameters of the composites. The results show that the values of t(1/2) for iPP/MCCs composites are lower than that for PP. The value of F(T) systematically increases with increasing relative degree of crystallinity. Non-isothermal crystallizations of iPP/MCCs composites correspond to tridimensional growth with heterogeneous nucleation and MCCs acted as nucleating agent in PIP matrix. The addition of microcrystalline cellulose has greatly reduced the spherulitic size of PP.