Improvement on the Efficiency of Drawing during the Production of Microfibrillar Composites

Abstract

The feasibility of manufacturing microfibrillar composites (MFCs) and their novel applications have been studied to a significant extend. In order to achieve commercially viable production rate of MFC materials, consistent fabrication has to be guaranteed. However, it has been shown that continuous production of MFC materials has certain difficulties need to be overcome. This study aims at identifying the production problems and improving the efficiency of manufacturing MFC materials. MFC manufacturing has been reasonably successful by drawing poly(ethylene terephthalate) (PET)/polypropylene (PP) blends. However, when the PP in the polymer blends is replaced by polyethylene (PE) for its ease of subsequent manufacturing, irregular breakage persistently occurs during drawing and this phenomenon also occasionally happens for PP/PET blends. This study involves melt blending of linear low density polyethylene and linear medium density polyethylene with PET in a single screw extruder with 70/30 wt%. Drawing was conducted at temperatures ranging from room temperature to 70°C and with draw ratios of between 1:5 and 1:7. The test results, when comparing MFC with pure PE, show 60% and 80% increase in specific tensile strength and specific tensile stiffness, respectively. It is concluded that by carefully controlling the temperature profile within the drawing chamber and using a moderate draw ratio (1:5), an efficient drawing process can be achieved to produce commercial MFC materials.