Synthesis and physico-chemical properties of polyphenyl silsesquioxanes

A new, higher yielding synthetic route towards dodecaphenyl cage silsesquioxanes: synthesis and mechanistic insights

“…9 In particular, phenylsilsesquioxanes, known for their superior thermal stability, have been the center of attention since Brown's comprehensive study in the 1960s, 13 and Andrianov's studies in the 1970s. 14 However, syntheses of singular isomers of cage silsesquioxane compounds have been arduous 15,16 due the many variables involved, including monomer type, catalyst species, water concentration, solvent, and reaction temperature. The hydrolysis of trichlorosilane monomers under aqueous conditions has been shown to produce cage, partial cage, and sol-type silsesquioxanes, 13 but low yields, long reaction times exceeding months, high temperatures, and additional steps 16 to isolate the different isomers have rendered these syntheses tedious for large scale production.…”

A Versatile Equilibrium Method for the Synthesis of High-Strength, Ladder-like Polyphenylsilsesquioxanes with Finely Tunable Molecular Parameters

“…Polymers 2021, 13, 4452 2 of 16 They identified various factors that affect the molecular weight and structural characteristics of the resulting polymers [20,21]. An important result was obtained in a study that demonstrated the reversible nature of the polymerization reaction and the stability of the most thermodynamically stable form of polyhedral octaphenylsilsesquioxane.…”

A Study of the Polycondensation of (Tetrahydroxy)(Tetraaryl)Cyclotetrasiloxanes under Equilibrium and Non-Equilibrium Conditions in the Presence and Absence of Montmorillonite

“…This indicates that steric parameters of a monomer can substantially affect the results of polymerization or polycondensation processes of organocyclosiloxanes. Due to the hydrodynamic and electro-optical characteristics of LPPSSO solutions, the differences in the α-values in the Mark–Kuhn–Houwink equation and the Kuhn segment were revealed depending on the ladder polymer structure, production method, organic substituents at the silicon atoms, and the structure of the prepolymer [ 6 , 7 , 8 , 9 ]. Despite the fact that 50 years have passed, interest in the steric characteristics of the polymers, these hybrid CL LPPSSO and other CL ladder polyorganosilsesquioxanes (LPOSSO), persists.…”

“…Despite the fact that 50 years have passed, interest in the steric characteristics of the polymers, these hybrid CL LPPSSO and other CL ladder polyorganosilsesquioxanes (LPOSSO), persists. This is because LPOSSO are known to be highly thermostable, to possess good mechanical parameters, and to be capable of forming thin films [ 1 , 7 , 10 ]. These properties apparently depend on the structure and the steric characteristics of the polymers.…”