Effect of blend composition on the morphology and mechanical properties of microfibrillar composites

Various blend compositions of polyethyleneterphthalate (PET) and polyamide 6 (PA 6) were used to prepare microfibrillar composites (MFC's) in form of thin ribbons. Steps for preparation were: (1) blending, (2) extrusion, (3) fibrillation, and (4) isotropization. The latter step was performed at a temperature condition above the melting temperature of PA 6, but below that of PET. In this way PET microfibrils remained as reinforcing elements in the PA 6-matrix. Depending on the actual PET/PA 6 ratio, various fibril arrangements in terms of fibril length and uniformity of fibril distribution could be achieved. A reasonable improvement in mechanical properties was reached already at 30 wt. % PET in PA 6 which was in terms of tensile strength higher than a 30 wt. % short glass fiber filled PA 6 system.