Segmented copolymers with telechelic poly (2,6-dimethyl-1,4-phenylene ether) (PPE) segments and crystallizable bisester tetra-amide units (two-and-a-half repeating unit of nylon-6,T) were studied. The copolymers were synthesized by reacting bifunctional PPE with hydroxylic end groups with an average molecular weight of 3500 g/mol and bisester tetra-amide units via an ester polycondensation reaction. The bisester tetra-amide units had phenolic ester groups. By replacing part of the bisester tetra-amide units with diphenyl terephthalate units (DPT), the concentration of tetra-arnide units in the copolymer was varied from 0 to 11 wt%. Polymers were also prepared from bifunctional PPE, DPT, and a diaminediamide (6T6-diamine). The thermal and thermal mechanical properties were studied by DSC and DMA and compared with a copolymer with flexible spacer groups between the PPE and the T6T6T. The copolymers had a high T. of 180-200 degrees C and a melting temperature that increased with amide content of 220-265 degrees C. The melting temperature was sharp with monodisperse amide segments. The T-m-T-c was 39 degrees C, which suggests a fast, but not very fast, crystallization. The crystallinity of the amide was similar to 20%. The copolymers are semicrystalline materials with a high T-g, and a high T-g/T-m ratio (> 0.8). (c) 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 512-518, 2007