Physical Properties of Polyamide 6 Fibre Coated with Thermoplastic Polyurethane Thin Film

Polyamide 6 (PA6) monofilament fibres were coated with thermoplastic polyurethane (TPU) thin film. The TPU was prepared from poly (ethylene adipate) glycol, 4, 4'-diphenylmethane diisocyanate (MDI) and 1, 4-butanediol (BD) with an NCO Index of 1.05. The structural changes in the fibre were analysed by the microscope FT-IR ATR scanning mode. It was found that structural changes occurred in the PA6 fibres due to TPU coating. There was a transformation from an amorphous phase to the alpha-crystalline phase resulting in the increase of crystallinity of PA6 fibre. An increase in strength as well as elongation was observed in the case of TPU coated fibres. The Young's modulus too showed an increase in strength. The improvement in the mechanical properties of coated PA6 was due to the crystalline changes in the fiber the annealing effect, the interface stiffening due to the interaction of the urethane group of TPU and the amide group of polyamide fiber as well as the role played by micro-cracks. The blending method is usually used for the performance improvement of PA6 fibres. The improvement of mechanical properties with a soft thin TPU coating seems very interesting and important. Also the TPU coated PA6 fibres had enhanced mechanical properties and possess a degradable nature when compared to the normal PA6 fibres.