On the crystallinity and some structure/property relationships of poly(ethylene terephthalate)-poly(amide-6,6) blends

Following the ester‐amide interchange reaction in the poly(ethylene terephthalate)/poly(amide‐6, 6) (PET/PA) system in the presence of p‐toluenesulfonic acid (TsOH), samples were injection molded and tested in the tensile mode. A brittle fracture was observed for these unoriented specimens. To separate the influence of the crystallinity from that of the interphases, the samples were studied using differential scanning calorimetry (DSC). The DSC results indicated an increase of crystallinity in the blends caused by enhanced nucleation of PA (which crystallizes first) and that of the copolymer resulting from the esteramide interchange reaction. It has been independently verified that neat PET samples of comparable crystallinity to that existing in the PET/PA blends show a similar behavior.