Polydiphenylsiloxane–polydimethylsiloxane–polydiphenylsiloxane triblock copolymers

Abstract

Polydiphenylsiloxane–polydimethylsiloxane–polydiphenylsiloxane triblock copolymers were prepared by two methods. The first approach was the sequential addition of the monomers. The anionic polymerization of hexamethylcyclotrisiloxane initiated by dilithio diphenylsilanolate gave α,ω‐bis(lithio dimethylsilanolate)polydimethylsiloxane, which was added to hexaphenylcyclotrisiloxane at ∼120 °C to yield the desired triblock material. In the other, a convergent approach was used. Excess α‐vinyldimethylsiloxypolydiphenylsiloxane was coupled to α,ω‐bis(hydrido)polydimethylsiloxane by a Pt‐catalyzed hydrosilylation reaction to give the triblock material. The formation of distinct blocks with regular microstructures in these materials was confirmed by 1H, 13C, and 29Si NMR spectroscopy as well as differential scanning calorimetry. The molecular weights were determined by gel permeation chromatography, and the thermal stabilities were evaluated by thermogravimetric analysis. Dynamic mechanical analysis was used to confirm thermal transitions obtained by differential scanning calorimetry and to evaluate the mechanical properties of the materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3629–3639, 2006

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

“…This is supported by the 29 Si chemical shift values for polymer S1, which are very close to the values reported for polysiloxanes bearing the same substituents. 22 Therefore, in the 29 Si{ 1 H}CP-NMR spectrum of polymer S1 (Fig. 2a) the main peak at −43.8 ppm and the small signal at −20.8 ppm are assigned to (Ph) 2 Si(NCN) 2 sites and terminal Si(Ph) 2 Cl groups, respectively.…”

Silicone containing copolymers: Synthesis, properties and applications

“…Due to the short segment lengths used, DSC analysis showed a single T g for the copolymers obtained, which increased linearly with diphenylsiloxane content in the copolymer (76). All silicone copolymers were also obtained through the Pt-catalyzed reaction of αvinyldimethylsiloxypolydiphenylsiloxane and α,ω-bis(hydrido)polydimethylsiloxane (35).…”

Dually crosslinkable SiO2@polysiloxane core–shell nanoparticles for flexible gate dielectric insulators

“…TMMS and DEPS were added to increase the mechanical exibility and electrical properties of the gate dielectric lms, respectively. [36][37][38] Finally TEOS was introduced to compensate the decient reaction sites occupied by the phenyl groups of DEPS. 39 The composition of the monomer mixture was optimized to 15 mol%, 20 mol%, 35 mol%, 15 mol% and 15 mol% for GPTS, MPTS, TMMS, DEPS and TEOS respectively.…”