Synthesis and characterization of hyperbranched poly(silyl ester)s

Hyperbranched poly(silyl ester)s were synthesized via the A 2 + B 4 route by the polycondensation reaction. The solid poly(silyl ester) was obtained by the reaction of di‐ tert ‐butyl adipate and 1,3‐tetramethyl‐1,3‐bis‐β(methyl‐dicholorosilyl)ethyl disiloxane. The oligomers with tert ‐butyl terminal groups were obtained via the A 2 + B 2 route by the reaction of 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl‐trisi1oxane with excess amount of di‐ tert ‐butyl adipate. The viscous fluid and soft solid poly(silyl ester)s were obtained by the reaction of the oligomers as big monomers with 1,3‐tetramethyl‐1,3‐bis‐β(methyl‐dicholorosilyl)ethyl disiloxane. The polymers were characterized by 1 H NMR, IR, and UV spectroscopies, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The 1 H NMR and IR analysis proved the existence of the branched structures in the polymers. The glass transition temperatures ( T g 's) of the viscous fluid and soft solid polymers were below room temperature. The T g of the solid poly(silyl ester) was not found below room temperature but a temperature for the transition in the liquid crystalline phase was found at 42°C. Thermal decomposition of the soft solid and solid poly(silyl ester)s started at about 130°C and for the others it started at about 200°C. The obtained hyperbranched polymers did not decompose completely at 700°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3430–3436, 2006