Synthesis and bulk characterization of new P(CB-b-S) diblock copolymers

✍ Scribed by V. W. Stone; A. M. Jonas; R. Legras; P. Dubois; R. Jerome

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 234 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990115)37:2<233::aid-pola13>3.0.co;2-g

✦ Synopsis

Strongly asymmetric chlorinated polybutadiene-b-polystyrene, [P((CB) x -b-(PS) y )] diblock copolymers with increasing x/( x ϩ y) ratios (up to 5.2 mol %) have been synthesized by the selective chlorination of the polybutadiene (PB) block in solution. Chlorination has been performed in anhydrous dichloromethane added with an antioxidant [2,2Ј-methylenebis-(6-tert-butyl-4-methyl-phenol)], at Ϫ50°C, under a continuous Ar flow and in the dark. Under the optimized experimental conditions, the PB chlorination is not complete, but the PS block is left unmodified. Even in the presence of a large chlorine excess (Cl 2 /butene unit molar ratio of 2.5), the experimental degree of chlorination of homo PB does not exceed 85%. The chlorinated copolymers have been characterized by 1 H-NMR, IR spectroscopy, size-exclusion chromatography, and elemental analysis. The chlorinated copolymers have also been studied by DSC and SAXS after annealing at 150°C. Although at this temperature the parent homopolymers are immiscible, no microphase separation has been observed for the block copolymers.