Transfer molding has been increasingly used to process polymer composites with various shaped nanoparticles, including platelet type nanoparticles. Platelet nanoparticles exhibit high aspect ratios (length to thickness); therefore their distributions in polymer matrix can be greatly affected by the flow trajectories in the mold. In present study, the clay platelet-polyethylene nanocomposite was prepared by transfer molding. The orientation of clay platelets developed during molding process was analyzed and measured with wide angle X-ray diffraction. Due to large velocity and shear stress gradients in the mold, the platelets caught in surface regions were rotated towards the flow direction and formed the oriented morphologies. With weaker shear stresses at the central region, the platelets were mostly randomly distributed. The shear stresses may be amplified locally at regions near the mold walls, which can further lead to or accelerate the orientations of clay particles. The orientation distribution was found to depend upon the clay fraction and sample size. The oriented platelets can be re-randomized through the annealing process. The orientation of clay platelets enhanced the orientation of polyethylene lamellae and caused shear band formation in composites when deformed.
|Number of pages||10|
|Journal||Polymer - Plastics Technology and Engineering|
|State||Published - Aug 2013|
Bibliographical noteFunding Information:
This work is supported by NSERC Canada and the Natural Science Foundation of Hebei Province of China (No. 2012202114).
- X-ray diffraction
ASJC Scopus subject areas
- Materials Science (miscellaneous)
- Chemical Engineering (all)
- Polymers and Plastics
- Materials Chemistry