Branched and Network Polysilanes as Cleavable Macrophotoinitiators

Abstract

The branched polysilane [(PhMeSi)0.8‐co‐(Et3Si(CH2)2Si)0.2]n (PS‐1) as well as the network polysilane [Et3Si(CH2)3Si]n (PS‐2) have been investigated as new polymerization photoinitiating structures. The behavior of PS‐1 was compared with that of [(PhMeSi)]n to demonstrate the enhancement of the photoinitiation for the branched system. As a result of the Si–Si bond cleavage under light and the formation of reactive silyl radicals or silyl cations, these compounds act as efficient photoinitiators (PIs) for free radical photopolymerization (FRP) and free radical promoted cationic polymerization (FRPCP). The polymerization initiating ability of PS‐1 is higher than that of PS‐2 under air. The initiating ability for the ring‐opening polymerization of epoxides is excellent for PS‐1. These polymeric PIs overcome the classical oxygen inhibition in FRP or FRPCP.

Zirconium Propoxide: A Coupling Agent for the Synthesis of Multifunctional Photoinitiators

“…Polysilane has been an exceptional example of polymeric PIs due both to its simple preparation and its multiple desirable properties . In the absence of organic catalyst, chlorosilanes can be polymerized by means of a Wurtz coupling, forming polysilanes with varied chain lengths and configurations, which can generate multiple primary radicals . However, one of the major issues is the synthetic procedure which could drastically impact the interest of the PI.…”

“…[11] In the absence of organic catalyst, chlorosilanes can be polymerizedb ym eans of a Wurtz coupling, formingp olysilanesw ith varied chain lengths and configurations, which can generate multiple primaryr adicals. [12] However,one of the major issues is the synthetic procedure which could drastically impact the interest of the PI. Therefore, we still require af acile methodt os ynthesize highmolecular-weight PIs.…”

Functionalized hyperbranched polysilanes for UV photoinitiator application

“…聚硅烷是一类以硅-硅键为骨架的有机 硅高分子, 在紫外区具有高的摩尔吸光系数, 而且在 紫外光照下能高效产生硅自由基引发光聚合 [16] . 由 于其突出的紫外光引发聚合性能, 油溶性 [ 1 7 ] 、水 性 [18,19] 、超支化聚硅烷光引发剂 [20] 被相继开发出来. [16,28] .…”

Light-Triggered Radical Silane-Ene Chemistry Using a Monosubstituted Bis(trimethylsilyl)silane

“…New reactive silanes could also be used as radical reducing agents or type II coinitiators . Multifunctional silanes (e.g., polysilanes) have also been reported as macrophotointiators for free radical polymerization . By studying the chemical bond dissociation energy of SiH bonds for various silanes and the reactivity of silyl radicals toward the addition to enes, tris(trimethylsilyl)silane (TTMSSiH) has been identified as the most suitable component .…”

“…[21,22] Multifunctional silanes (e.g., polysilanes) have also been reported as macrophotointiators for free radical polymerization. [23,24] By studying the chemical bond dissociation energy of SiH bonds for various silanes [25] and the reactivity of silyl radicals toward the addition to enes, [26] tris(trimethylsilyl) silane (TTMSSiH) has been identified as the most suitable component. [25] However, aside from its great ability to undergo radical silane-ene reactions, multifunctional components based on TTMSSiH are not easily accessible.…”