Research On Characteristics Of HDPE/MMT Nanocomposites Prepared By Eccentric Rotor Extruder

HDPE/MMT nanocomposites, with good stiffness, toughness, thermal properties and barrier properties, were widely used in industry, agriculture, sanitation, medicine, daily necessities and so on. However, as the bad compatibility between nonpolar HDPE and polar MMT, dispersion and intercalation of MMT layers is hard to achieve by traditional screw extruder based on shear flow. Compared with shear flow field, extensional flow field has the incomparable advantage, which is more effective for dispersion and mixture.The eccentric rotor extruder not only achieved the whole process of polymer processing based on extensinal flow, but also has a streamlined, flawless and good-exhaust transport channel. The principle of polymer eccentric rotor plasticating and conveying method based on elongational flow was analyzed in this paper.HDPE/MMT nanocomposites were prepared by eccentric rotor extruder based on elongational flow, then the influence of processing temperature and rotor speed on the material structure and performance was researched. The result showed that compared with the processing temperature, the effect of intercalation and dispersion of MMT layers was more sensitive to rotor speed. The influence of process parameters on the melting point of materials was smaller, but on the crystallinity was opposite bigger, the influence of processing temperature was more obvious among these process parameters. When processing temperature was 220 °C and rotor speed was 50 rpm, tensile strength and elongation at break were greatly influenced by the process parameters, however, the change of hardness was relatively small.By changing the contents of MMT and compatilizer, the structure and properties of HDPE/MMT nanocomposites which prepared by eccentric rotor extruder were researched, and the functional mechanism of MMT under tensile force field in the HDPE matrix were analyzed. Studies showed that, under the extensinal flow field, the best exfoliation and/or intercalation of MMT layers were observed with suitable contents. The mechanics performance, thermal performance and crystallinity of HDPE/MMT nanocomposites were also improved. In addition, the increase of MMT, to some extent, improved the barrier performance of nanocomposites. The addition of the compatilizer further improved the interfacial interaction between HDPE and MMT phases, which was more efficient for exfoliation of MMT layers.