Dipole moments of (styrene-p-chlorostyrene) triblock copolymers in solutions

✍ Scribed by M. Shima; N. Yamaguchi; M. Sato; E. Ogawa

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 229 KB
• Volume: 19
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(83)90185-4

✦ Synopsis

Styrene-p-chlorostyrene) triblock copolymers of the ABA and BAB types (A--polystyrene; B--poly-p-chlorostyrene) were prepared by anionic polymerization and their conformational behaviours in solutions were studied from measurements of the dipole moments. Two solvents, toluene and cumene, were used for the study; toluene is a good solvent for both polystyrene and poly-pchlorostyrene whereas cumene is a selective solvent, good for polystyrene but poor for poly-pchlorostyrene. It was found that the dipole moments of the block copolymers measured in toluene are the same for the ABA and BAB copolymers; in cumene however the dipole moment of the BAB copolymer is smaller than that of the ABA copolymer. The results give an additional support to our previous conclusion that the conformation of the block copolymers in a good solvent such as toluene could be approximated with a pseudo-random coil form; in a selective solvent, however, some anomalies take place in the conformation of the block copolymers, as deduced from intrinsic viscosity, osmotic pressure and light scattering measurements.