Preparation and properties of polyhedral oligomeric silsesquioxane polymers

Abstract

Polyhedral oligomeric silsesquioxane (POSS) polymers were synthesized by the dehydrogenative condensation of (HSiO 3/2 ) 8 with water in the presence of diethylhydroxylamine followed by trimethylsilylation. Coating films were prepared by spin-coating of the coating solution prepared by the dehydrogenative condensation of POSS. The hardness of the coating films was evaluated using a pencil-hardness test and was found to increase up to 8H with increases in the curing temperature. Free-standing film and silica gel powder were prepared by aging the coating solution at room temperature. The silica gel powder was subjected to heat treatment under air atmosphere to show a specific surface area of 440 m 2 g −1 at 100• C, which showed a maximum at 400• C as 550 m 2 g −1 .

Facile synthesis of cyclosiloxane-based polymers for hybrid film formation

“…The dimethylsiloxane repeat units (R 2 SiO) in TMCS-DVHS hybrid polymer films contribute to the provision of more flexible elongation because of the nature of the longer dimethylsiloxane chains. 20 The pencil-hardness ratings of crosslinked TMCS-DTMS and TMCS-DVHS hybrid polymer films were tested and found to be HB and 4B respectively, demonstrating that the TMCS-DTMS hybrid polymer film was harder than the TMCS-DVHS hybrid polymer film because of the formation of silsesquioxane domain units in the crosslinked hybrid networks 19,48 and the lesser amount of dimethylsiloxane groups. Results of pencil hardness, elongation, and Young's modulus also indicate that the mechanical durability of hybrid polymer films increases concomitantly with increasing the amount of silsesquioxane crosslink units in hybrid polymer films.…”

Polysiloxanes Grafted with Mono(alkenyl)Silsesquioxanes—Particular Concept for Their Connection

“…The significant perspectives for polysiloxanes concern modification of their structure. It may be performed at the stage of polysiloxanes chain formation, i.a., anionic ring-opening polymerization of cyclic siloxanes, or hydrolytic polycondensation of two chloro/alkoxysilanes varying in functional groups [23,[31][32][33]. On the other hand, it may be achieved by modification of functional group present on the existing polysiloxane chain, mostly via catalytic reactions [34][35][36][37][38][39][40][41][42][43][44], to gain co-polymers with precise and tailored properties [45][46][47][48][49][50][51][52][53][54][55].…”

Hyperbranched Polysiloxanes Based on Polyhedral Oligomeric Silsesquioxane Cages with Ultra-High Molecular Weight and Structural Tuneability

“…HPCCPs have been prepared from octakis(dimethylsiloxy) octasilsesquioxane (Q 8 DMS ), which reacts with themselves or with phenylsiloxanediols through dehydrogenative polycondensation under certain catalysts [ 33 , 34 , 35 ]. However, the insufficient catalysis efficiency in these reactions failed to produce polymers with high molecular weight.…”