Synthesis and Structural Ordering of Gradient-Modulus Star Copolymers

✍ Scribed by Satoshi Uchida; Hisashi Takeda; Koji Ishizu

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 71 KB
• Volume: 213
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1999.6102

✦ Synopsis

Gradient-modulus star copolymers were synthesized by crosslinking of polystyrene/isoprene tapered anions with divinylbenzene in benzene. The styrene content in the tapered arm was determined by 1 H-nuclear magnetic resonance as a parameter of conversion. The composition of the arm showed the gradient structure and was in good agreement with that calculated by reactivity ratios. The solution properties of gradient-modulus star copolymers were examined by static and dynamic light scatterings. The structural ordering of gradient-modulus star copolymers were investigated by means of small-angle X-ray scattering. Gradientmodulus star copolymers formed a body-centered cubic (BCC) structure near the overlap threshold (C*). Above C*, this structure changed to the mixed lattice of BCC and face-centered cubic (FCC) structures.