Title: Chain mobility in bulky carbosilane modified polymeric siloxane systems
Abstract: Abstract Hydrosilylation of bulky carbosilanes [CH 2 =CHRC(SiMe 2 R') 3 , R=CH 2 , (CH 2 ) 3 or SiMe 2 ; R'=Me or Ph] with oligosiloxane precursors [M(D 2 D H ) 7 D 2 M, M(D 2 D H 2) 11 D 2 M, PDMS x% -PMHS 100-x% (x=85, 50, 30, 0)] was carried out. The relationship between the mobility of siloxane chain and the type of carbosilane moiety, as well as the type of distribution of carbosilane group along the polymer chain, was consecutively studied. Carbosilane substituents, due to their exceptional steric requirements, have been shown to strongly affect thermal properties of siloxane oligomers, implying a substantial change of the chain flexibility and free volume of modified oligomers.