Effects of Magnesium Hydroxide and Its Surface Modification on Crystallization and Rheological Behaviors of Polypropylene

In this article, polypropylene composites filled with magnesium hydroxide (PP filled with MH) were prepared in corotating twin-screw extruder. The effects of MH particles content and types of treatment agents on the crystallization and melting behaviors, crystal structure, and rheological properties of PP/MH composites were studied by differential scanning calorimetry (DSC), a wide-angle X-ray diffraction, and dynamic rheological measurements. The DSC results show that MH particles act as a good heterogeneous nucleation effect on PP. Surface treatment of MH weakens its heterogeneous nucleation effect. The nucleating efficiency of MH on PP is found to depend strongly on its content and type of treatment agents. The dynamic rheological behaviors of MH filled PP is found that the complex viscosity (eta(star)) increases with increasing MH content, whereas with increasing filler concentration the network structure becomes the prevailing process, which raises the eta(star) values, especially at the low frequency zone. The eta(star) values of the composites, however, decrease with the addition of various treatment agents. POLYM. COMPOS., 30:941-947, 2009. (C) 2008 Society of Plastics Engineers