섬유

Specific refractive index increments of oplyurethane/polydimethylsiloxane segmented copolymers

  • 출판일2001.03
  • 저자
  • 서지사항
  • 등록일 2016.11.02
  • 조회수 263
New polydimethylsiloxane-containing segmented block copolyurethanes were obtained from aromatic or aliphatic diisocyanates, 1,4-butanediol and poly(ethylene glycol)adipate using a multistep polyaddition process. Specific refractive index increments of these segmented copolymers in N,N-dimethyl-formamide have been determened by the Lorenz-Lorentz equation and the corresponding group contributions to the molar refraction and to the molar volume. The results are in good agreement with the experimental values. Also, from the dependence between the specific refractive index increments and the weight fraction of 4,4'-methylene diphenylene diisocyanate units, wd, the v0 and dv/dwd coefficients have been evaluated and the results are situated between the values reported in literature.
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