Segmented block copolymers of polysulphone with monodisperse amide segments were synthesized by a melt and a solution polymerization method. Both triblock and multi-block copolymers were prepared. The length of the difunctional polysulphone was varied from 2000 to 20,000 g/mol. The monodisperse amide segment was the tetra-amide T6T6T based on terephthalic acid (T) and hexamethylene diamine (6) units. The main goal of this work was to study if the high T-g amorphous polysulphone could be modified to a high T-g semicrystalline PSU-T6T6T copolymer. The copolymers were characterized by viscosity measurements, NMR, FTIR, MALDI-TOF, DSC, and DMA. Depending on the amide concentration in the copolymers the T6T6T melting temperatures ranged between 220 and 270 degrees C and thus the crystallization window was small 50-100 degrees C. From the FTIR results, it was revealed that the crystallinity of the T6T6T segments in the copolymer could be very high, up to 92-97%. The T6T6T has crystallized out into nano-ribbons with a high aspect ratio. These high T-g semi-crystalline copolymers had a high dimensional and solvent resistance. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 63-73, 2010