Effect of deformation on the surface composition of multicomponent polymers. II. Blends of polydimethylsiloxane–polysulfone block copolymers in polychloroprene

✍ Scribed by M. M. Gorelova; A. J. Pertsin; I. O. Volkov; N. B. Sanches; A. S. Gomes

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 199 KB
• Volume: 69
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980919)69:12<2349::aid-app6>3.0.co;2-8

✦ Synopsis

The effect of uniaxial stretching on the surface composition of dilute blends of polydimethylsiloxane/polysulfone 2500/44,000 and 2500/3500 block copolymers in polychloroprene is studied using X-ray photoelectron spectroscopy. The surface of the initial (unstretched) blends is found to be covered by a discontinuous copolymer overlayer with a thickness greater than the XPS sampling depth. The stretching leads to a substantial drop in the extent of the copolymer surface segregation. For the 2500/ 3500 block copolymer, the dependence of the surface composition of the blends on the stretching degree is well described by a homogeneous deformation model, whereas for blends of the 2500/44,000 copolymer, the stretching of the copolymer overlayer lags noticeably behind that of the polychloroprene matrix. In the blends of the 2500/3500 copolymer, the stretching has practically no effect on the distribution of the copolymer components in the near-surface region. By contrast, the 2500/44,000 copolymer shows a substantial surface depletion of siloxane with stretching.