Ethynyl siloxanes

Recently, Kolel-Veetil and Keller have modified this system to produce elastomeric networked polymers. The ambient-condition hydrosilation reactions between monomeric vinyl- or ethynyl-terminated carboranylenesiloxane and three different monomeric branched siloxane cross-linkers in hexane yielding these systems were catalyzed by the Karstedt catalyst.134 The reactions involving the vinyl-carboranylenesiloxane were reported to produce a set of completely hydrosilated networked polymers (105) (Fig. 65). In the case of the ethynyl monomer, the reactions were carried out at two different ratios, yielding a partially (106) and a com-... 

Figure 65 The hydrosilated networked polymers 105, 106, and 107 obtained from Karstedt catalyst-catalyzed hydrosilations involving monomeric vinyl- or ethynyl-terminated carboranylenesiloxane and a branched siloxane cross-linker in hexane. The Si-bound methyl groups have been omitted for clarity. (Adapted from ref. 134.)...

The utilization of allyl alcohol as the nucleophilic reagent to prepare dendritic carbo-siloxanes was also reported by Lang and Brilning134,135. Using a second generation allyl-terminated carbosiloxane dendrimer, they were able to attach titanium moieties via a simple hydrosilylation reaction (equation 12)134. Lang and coworkers were also successful in binding cobalt moieties to ethynyl-terminated carbosiloxane dendrimers (e.g. equation 13)136,137. 

In the interest of producing elastomeric network polymers, Kolel-Veetil et al. reported the modification of the preceding hydrosilation reaction system. They reported the Karstedt catalyst-catalyzed ambient-condition hydrosilation reactions of a monomeric vinyl 14 or ethynyl-containing 17 carboranylenesiloxane with three different monomeric branched siloxane crossUnkers in hexane (Figure 15.19) [36]. The reactions involving the vinylcarboranylenesiloxane were reported to... 

Crosslinked films were prepared from these PDMS-b-PEO copolymers by hydrosilylation reaction between the terminal vinyl groups and multi hydride functional poly(dimethyl-co-methylhydride siloxane) (9), which was a commercial sample from Bayer (CA 730). A Si-H/vinyl ratio of 3 was used. Again Pt(0) was used as a catalyst and ethynyl cyclohexanol as an inhibitor, which prohibited curing before raising the temperature to 115 °C. 

---