Poly(hydrosilane)s as Sources of Silyl Radicals and Their Use as Polymerization‐Initiating Structures

Abstract

Poly(hydrosilane)s, [R(H)Si]n [R = Ph, Si(CH2)3SiMe2Th, cy‐Hex], are investigated as sources of silyl radicals. The Si–H bonds in these oligomers exhibit good to excellent hydrogen donating properties which ensure the formation of reactive silyl radicals. For free radical photopolymerization, the polymerization initiating properties of these structures are checked. These polymers are found to be advantageous to overcome the classical oxygen inhibition of the FRP process. Their ability in FRPCP is also evaluated for an epoxy monomer. The mechanisms are investigated through ESR and laser flash photolysis experiments. magnified image

Sole‐Component Visible Macrophotoinitiators with Si‐H: Decreased Oxygen Inhibition and Modified Cured Polymer Materials

“…[16] Another silyl radical also could be regenerated by the reaction G in Scheme 2. Therefore, in TX-PMHSs systems, the dissolved oxygen could be consumed by silyl radical from all the pathways; [16,42] and back electron transfer derived from dissolved oxygen was not apparent in comparison with that in TXÀ A system. The more SiÀ H, the faster oxygen consumption, and the rapid photolysis was obtained during the first 0.5 h.…”

Inorganic and organometallic polymers

“…47 The novel use of various poly(hydrosilane)s 12 as radical initiators was reported; this work provides another potential synthetic tool for the controlled radical polymerisation of olefins. 48 Helical polydiarylsilanes featuring one chiral side-group at each silicon centre have been shown to aggregate into ordered structures that undergo emission of circularly polarised light when excited with a high energy unpolarised light source. 49 The controlled electropolymerisation of diorganodichlorosilanes R 2 SiCl 2 enabled the synthesis of well-defined polysilane block copolymers such as [PhSiMe] m -b-[BuSiMe] n to be prepared.…”

Branched and Network Polysilanes as Cleavable Macrophotoinitiators

“…A similar photoinitiating ability was previously found for poly(hydro)silanes [R(H)Si] n (R = alkyl or phenyl). [ 21 ] A polymerization comparison between the linear polysilane [PhSiMe] n and the branched derivative PS-1 is also very useful to unambiguously demonstrate that there is an enhancement of photo-initiation for the branched system (Figure 3 A: curve 2 vs curve 3).…”