In-situ Composite Based on Poly (ethylene terephthalate), Polyamide and Polyethylene with Microfibres Formed through Extrusion and Hot Stretching
In—situ Composite Based on Poly （ethylene terephthalate）,Polyamide and Polyethylene with Microfibres Formed through Extrusion and Hot Stretching

In-situ composites based on dispersed poly (ethylene terephthalate) (PET) or polyamide (PA), and continuouspolyethylene (PE) were prepared through a single screw extruder of Haake rheometer system with a rod-die relativelysmall in diameter. The extrudate was drawn at a drawing ratio of 3.1, and then quickly cooled in cold water. Thespecimens were obtained by injection molding at processing temperatures less than 190℃, far below the meltingtemperature of PET (265℃) and PA (230℃), which can maintain the solid state of PET and PA microfiber phasein the composites. Morphological observation with scanning electron microscopy (SEM) indicated that PET and PAcan more or less form in-situ microfibers at compositions studied (0～20 wt pct PET or PA), and especially, PETand PA were almost deformed into fibers at the concentration of 15 wt pct. Tensile strength and modulus of theblends reinforced by PET or PA microfibers showed to be increased from the tensile test results. The most noticeableimprovement of the tensile properties occurred at 15 wt pct of PET in PET/PE system, corresponding to the highestmicrofiber content, where the tensile strength reached 32.5 MPa, whereas only 19.5 MPa for the pure PE.