Effect of Mechanical Milling on the Thermal Behavior of Polyethylene Reinforcedwith Nano-sized Alumina

Abstract

In the current study the dependency of morphology and thermal<br><br>behavior of medium density polyethylene (MDPE) powder<br><br>reinforced with 0, 5, 10 and 15 wt.% nano-sized Al2O3 particles<br><br>on mechanical milling were studied. The effects of milling<br><br>time on the morphology and the thermal behavior were investigated<br><br>by Transition Electron Microscopy (TEM), Scanning<br><br>Electron Microscopy (SEM), Differential Scanning Calorimetery<br><br>(DSC) and Thermo Gravimetric Analyzer (TGA). The<br><br>TEM micrographs obtained from the nanocomposites proved<br><br>that mechanical milling could be an adequate method to disperse<br><br>nano-sized hard particles throughout the polymer. The<br><br>SEM micrographs of pure MDPE showed that regular shape<br><br>powder converted to the flake shapes as milling time increased.<br><br>Also the results illustrated that an increase in milling time<br><br>caused to decrease the agglomeration of alumina. The DSC<br><br>profiles of samples elucidated that ball milling had little effect<br><br>on crystalline temperature and melting point of all materials<br><br>including MDPE and its nanocomposites. The nanocomposite<br><br>exhibited more thermal stability than pure polyethylene proved<br><br>by TGA tests.