The Effect of Multiple Extrusions on the Properties of Montmorillonite Filled Polypropylene

Abstract

Nanocomposites have attracted a great deal of interest during recent years. Much research has been conducted towards the incorporation of clay particles in a polypropylene matrix. However, the effect of extrusion reprocessing on the material properties has not been studied in depth. In this study, composites of polypropylene (PP) reinforced with organic modified montmorillonite (MMT) (4 wt%) and coupling agent were subjected to 15 extrusion cycles. The materials were characterized by melt flow index (MFI), plate-plate rheometry, tensile testing and impact measurements, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed an improved intercalation of the MMT clay in the first few extrusions, thus improving the mechanical properties. Increasing the processing steps furthermore lead to a decrease in elastic modulus and impact strength, which was attributed to a reduction in matrix-filler interaction, most probably caused by organoclay degradation as shown by thermogravimetric analysis (TGA). The results of this study provide a useful insight in either the recycling of PP/MMT waste streams or the use of clay particles as a strengthening filler agent in the recycling process of different polymer waste streams.

Influence of Repeated Injection Molding Processing on Some Mechanical and Thermal Properties of Wood Plastic Composites

“…Because there was no comparable research found in the search of the literature, the findings of this study were compared with studies of WPCs reproduced by re-extrusion (Yarahmadi et al 2001;Delva et al 2014). In these studies, the properties of WPCs manufactured with the re-extrusion process were reduced with an increase in the number of re-extrusion cycles.…”

Structure-properties relationships in melt reprocessed PLA/hydrotalcites nanocomposites

“…Recently, polymer nanocomposites, have received a great interest because they exhibit good mechanical, thermal and barrier properties [14,15]. Due to the growing market of nanocomposites, the scientific literature has currently studied the effect of reprocessing of the nanocomposites based on conventional polymers [13,[16][17][18][19]. Moreover, several studies investigated the effect of the reprocessing on the properties of neat biodegradable polymers, such as PLA [5,6,8,20].…”

Study on the properties of polyethylene/montmorillonite nanocomposites prepared by a novel vane mixer

“…After that, a longer mixing time has little effect on further exfoliation and intercalation of MMT layers. In previous work, the effect of extrusion cycles on PP/MMT under shear stress was studied. In that work, the XRD analyses also show the increasing mixing time could not led an exfoliated structure in the nanocomposites.…”

“…The tensile properties increase at first may be because the intercalated nanostructures can be obtained even when the mixing time is 1 min, which is determined by XRD analyses. In previous work, it is shown that the longer mixing time decreases tensile properties. Delva et al .…”

“…Some works have been done on the theoretical analysis of thermodynamics and kinetics . However, there are few works about the effect of machining process on the properties of polymer/clay nanocomposites . Sharma et al .…”