Photoinduced Polysiloxane Architectures from Spirosiloxane Precursors via Intramolecular Hydrosilylation

Abstract

In this letter a method is described to synthesize new polysiloxane architectures by photoacid catalysis. An oxasilaspirocycle is designed that is able to undergo a photoacid generator catalyzed ring-opening reaction leading to either a homopolymer or to copolymers with hydroxyl-terminated polydimethylsiloxane. These polymers feature a defined amount of double bonds in the backbone, which is controlled by the ratio of oxasilaspirocycle to the comonomer. The former was prepared by trispentafluorophenylborane-catalyzed intramolecular hydrosilylation of a dialkenyloxysilane with an appropriate structural motif. The UV-initiated polymerization was characterized via in situ IR spectroscopic studies to determine the rate of reaction.

Ring-Opening Polymerization—An Introductory Review

“…Typical examples are triphenylsulfonium triflate and diphenyliodonium triflate. The latter has been studied recently [66] to selectively cleave the carbon-oxygen bonds in a vinyl functionalized oxasilaspirocycle to form both homo-and copolymer polysiloxanes via a double ring-opening CROP (cf. Section 2.3, see Figure 23).…”

Synthesis of spirocyclosiloxanes for transparent copolymer thermosets

“…By avoiding the synthesis and manipulation of long chain polymers, this approach offers the chance to take the benefit of good virtues of small molecules, such as low viscosity, good miscibility, and high purity, and has therefore been increasingly drawing attention from the scientific community. [3][4][5][6][7][8][9][10][11][12][13][14][15] The ring opening reaction of multiple-ring small cyclic molecules provides an additional and versatile approach to prepare crosslinked polymeric materials directly from small molecules. Single ring cyclic molecules lead to linear polymers when they are rendered to ring-opening reactions, but those with two or more rings will generate crosslinked materials in the presence of suitable catalysts.…”

“…The popular epoxy resin is actually made in this way, and its successful commercialization has served to excite researchers to investigate deeper in this direction. Until now, numerous multiple-ring cyclic molecules other than epoxides [2][3][4][5][6][7][8] have been reported with demonstrated use in the preparation of novel polymers and advanced materials. [9][10][11][12][13] For example, Yang et al reported the formation of biodegradable polycarbonate network by the crosslinker molecule, bis(trimethylene carbonate), and investigated the relationship between the amount of the crosslinker and the degradation rate.…”

“…One of well‐known such processes is the copolymerization of styrene and divinylbenzene in the production of commercialized styrene–divinylbenzene resin, which has widely been used as packing materials, solid support, GPC stationary phases, and so on. By avoiding the synthesis and manipulation of long chain polymers, this approach offers the chance to take the benefit of good virtues of small molecules, such as low viscosity, good miscibility, and high purity, and has therefore been increasingly drawing attention from the scientific community …”

Multi-functional ladderlike polysiloxane: synthesis, characterization and its high performance flame retarding bismaleimide resins with simultaneously improved thermal resistance, dimensional stability and dielectric properties

“…18 Therefore ladder-like polysiloxane may be a suitable structure for developing new high-performance ame retardants. However, polysiloxanes generally have considerably different solubility parameters to other polymers, 19 leading to difficulties in endowing the modied polymers with the outstanding properties of polysiloxanes due to poor dispersion. Hence, to be a good ame-retardant, ladder-like polysiloxane should have functional groups that can react with the polymer.…”