End-capped siloxane oligomers

Tough, transparent, heat and flame resistant, multiblock (bisphenol fluorenone carbonate) (BPF)-dimethylsiloxane copolymers have been synthesized by interfacial polycondensation of phosgene with various mixtures of BPF end-capped siloxane oligomers and free BPF or its monosodium salt 232). Siloxane content of the copolymers were varied between 7 and 27%. Presence of two Tg s, one below —100 °C and the other as high as 275 °C, showed the formation of two-phase morphologies. 

Scheme III. Use of end-capped siloxane oligomers. R is C2Hs- The polycondensation reaction is not balanced stoichiometrically.

Figure 2.13 Synthesis of eugenol end-capped siloxane oligomers.

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