In Situ Fibrillar Reinforced PET/PA-6/PA-66 Blend

摘要

Ternary fibrillar reinforced blends are obtained by melt-blending of poly(ethylene ~rephthalate) (pgn. polyamide 6 (PA-6) and polyamide 66 (PA-66) (20/60/20 by 'eight) in the presence of a catalyst. followed by cold drawing of the extruded ristles to a draw ratio of about 3.4 and additional annealing of the drawn blend at 20 or 240°C for 4 or 8 h. The blend samples are studied by DSC. X-ray diffraction. EM. and static and dynamic mechanical testing (DMA). SEM and DMA show that A-6 and PA-66 fonD a homogeneous. continuous matrix in which PET regions are ispersed. X-ray and DSC measurements of the drawn and annealed at 220°C amples suggest mixed crystallization (solid solubility) of PA-6 and PA-66. and ooperative crystallization of PET with the two polyamides. Mer annealing at 240°C I.bove the melting point of PA-6 and below that of PET). the polyamide matrix ecomes partially disoriented. while the oriented. fibrillar PET is preserved and lays the role of a reinforcing element. The DSC results for the same samples sug- est in situ generation of an additional amount of copolymer. This additional opolyrnerization. together with that generated during blend mixing in the extruder . nproves the compatibility of the blend components (mostly at the PET -polyamide ~terface) and alters the chemical composition of the blend.