The melt-direct intercalation method was employed to prepare poly (propylene)(PP)-maleic anhydride grafted poly(propylene) (PP-g-MAH)-organic-montmorillonite (Org-MMT) nanocomposites. X-ray diffractometry (XRD) was used to investigate the intercalation effect, crystallite size, and crystal cell parameter in these composites. Two kinds of maleated PP, with graft efficiencies of 0.6 and 0.9 wt%, and two sorts of manufacturing processes were used to prepare nanocomposites and then to investigate their effects on intercalation behavior. The results showed that the intercalation effect was enhanced by increasing the content of PP-g-MAH, using maleated PP with higher graft efficiency, and adopting the mold process. The crystallite size of nanocomposites perpendicular to the crystalline plane, such as (040), (130), (111), and (041), reached the minimum value when the content of PP-g-MAH was 20wt%. This result indicated that the crystallite size of PP in nanocomposites decreased by proper addition of PP-g-MAH. Maximum values in tensile strength (40.2 MPa) and impact strength (24.3 J/m) were achieved when the content of PP-g-MAH was 10 and 20%, respectively

The nonisothermal crystallization kinetics of poly(propylene) (PP), PP-organic-montmorillonite (Org-MMT) composite, and PP-PP-grafted maleic anhydride (PPg-MAH)-Org-MMT nanocomposites were investigated by differential scanning calorimetry (DSC) at various cooling rates. Avrami analysis modified by Jeziorny and a method developed by Mo well-described the nonisothermal crystallization process of these samples. The difference in the exponent n between PP and composite (either PP-Org-MMT or PP-PP-g-MAH-Org-MMT) indicated that nonisothermal kinetic crystallization corresponded to tridimensional growth with heterogeneous nucleation. The values of halftime, Zc; and F(T) showed that the crystallization rate increased with the increasing of cooling rates for PP and composites, but the crystallization rate of composites was faster than that of PP at a given cooling rate. The method developed by Ozawa can also be applied to describe the nonisothermal crystallization process of PP, but did not describe that of composites. Moreover, the method proposed by Kissinger was used to evaluate the activation energy of the mentioned samples. The results showed that the activation energy of PP-Org-MMT was much greater than that of PP, but the activation energy of PP-PP-g-MAH-Org-MMT was close to that of pure PP. Overall, the results indicate that the addition of Org-MMT and PP-g-MAH may accelerate the overall nonisothermal crystallization process of PP.