Triblock Copolymers Based on Monohydroxy Polystyrene with Crystallizable Amide Segments: Synthesis and Characterization

Four series of triblock copolymers are studied, which are synthesized by reacting monofunctionalized polystyrene with crystallizable amide segments such as diamide (T phi T and T6T) and tetraamide (T6T6T and T6A6T). The difunctional amide segment consists of two terephthalic groups at the outside (T). The length of the soft segment changed from 1000 to 8000 g/mol using difunctionalized polystyrene (PSt) and thereby the concentration of the hard segment is varied from 35 to 4 wt%. The molecular weight of the triblock copolymer is determined by the inherent viscosity measurement method. The FT-IR results reveal that the degree of crystallinity of the amide segments in the copolymer is high 79%. The differential scanning calorimetry shows the T-g for amorphous polystyrene and T-m for crystallizable hard segments. Depending on the amide concentration in the copolymer, the diamide and tetraamide melting temperature ranged between 125 to 280 degrees C. All the thermogravimetric data reveal that the polymer shows single-stage decomposition temperature centered around 410 degrees C. The solvent resistivity of these materials is very high even at a low concentration of (4%) amide content. All the copolymers show low water absorption.