섬유

synthesis and properties of regular star polybutadienes with 32 arms

  • 출판일1999.03
  • 저자
  • 서지사항
  • 등록일 2016.11.02
  • 조회수 281
a dendrimer carbosilane containing 32 si-cl bonds in the perimeter has been prepared and has been used as a coupling agent to prepare 32-arm star polybutadienes. the dilute-solution properties $left angle bracket$ r//g**2 $right angle bracket$ , a//2, $left bracket$ $eta$ $right bracket$ , and d//0 have been measured in one good solvent and in one $theta$ -solvent. the dimensions of the 32-arm star polymers are compared with those of linear polymers at constant molecular weight. it is shown that the 32-arm star polybutadiene has the characteristic properties of a hard-sphere molecule in dilute solution. the equivalent hard-sphere radii calculated from a//2, d//0 and $left bracket$ $eta$ $right bracket$ are identical and 1.29 times larger than the root mean-square radius of gyration. the daoud-cotton scaling model for stars is also tested (author abstract) 25 refs
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