Visible Light–Induced RAFT Polymerization of Methacrylate with 4‐(<i>N</i>,<i>N</i>‐diphenylamino)benzaldehyde as Organophotoredox Catalyst and the Effect of Temperature on the Polymerization

Macro Chemistry & Physics

et al. 2022

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A direct photolysis reversible addition-fragmentation chain transfer (RAFT) polymerization of (meth)acrylates is developed with 2-cyano-2-propyldodecyl trithiocarbonate (TTP), which plays the dual role as photoinitiator and chain transfer agent. The polymerizations can be efficiently activated by blue light while maintaining a linear increase in M n versus conversion. With poly(methyl methacrylate)-TTP (PMMA-TTP, M n = 6700 g mol -1 , Ð = 1.29) as precursor, a higher molecular weight PMMA (M n = 14 600 g mol -1 , Ð = 1.67) by chain extension, and a series of block copolymers, including poly(methyl methacryalte)-b-poly(glycidyl methacrylate), poly(methyl methacrylate)-b-poly(tert-butyl methacrylate), and poly(methyl methacrylate)-b-poly(benzyl meacrylate)(PMMA-b-PBnMA), are prepared. The M n,NMR = 14 900 g mol -1 of PMMA-b-PBnMA measured by NMR is very close to M n,GPC = 14 200 g mol -1 determined by gel permeation chromatography. Furthermore, the polymerization of acrylates exhibits higher controllability in regarding to dispersity (Ð < 1.20) compared to those of polymethacrylates (Ð = 1.10-1.80). With poly(methyl acrylate) (PMA-TTP, M n = 11 900 g mol -1 , Ð = 1.09) as macro-RAFT agent, a higher molecular weight PMA (M n = 23 500 g mol -1 , Ð = 1.28) by chain extension, and PMA-b-PBnA (M n = 26 500 g mol -1 , Ð = 1.19) are also prepared. A positive synergic effect is demonstrated by enhanced apparent polymerization rates at elevated temperature. For example, the apparent polymerization rates of MA increases from 0.0860 to 0.115 h -1 with temperature rising from 32 to 50 °C.

“…This phenomenon is also mentioned in the light induced RAFT polymerization catalyzed by aromatic aldehyde derivatives. [76]…”

Section: Chain Extension and Block Polymerization With Pma-ttp As Macro-raftmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct Photolysis RAFT Polymerization of (Metha)acrylate with 2‐Cyano‐2‐propyldodecyl Trithiocarbonate as Mediator

Zhang

Duan

Macro Chemistry & Physics

et al. 2022

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“…Based on these reactions, a well-controlled reversible degenerative radical polymerization of methacrylate has been demonstrated. 29 Very recently, DPAB as a photoredox catalyst was also successfully used in synthesis of α,ω-dithiol and α,ω-divinyl telechelic polythioether oligomers through thiol-ene click polymerization of 1,4-benzenedimethane (BDMT) and diethylene glycol divinyl ether (DEGVE). 30 Thiol-ene click polymerization is of great advantage in surface modification for its insensitive to moisture and oxygen, and the availability of various functional monomers 31 These surface-anchored polymeric coatings demonstrate intrinsic properties of polymers, such as flexibility, biocompatibility, and stability.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, we found that 4‐( N , N ‐diphenylamino)benzaldehyde (DPAB) excited by visible‐light could be reductively quenched by a RAFT reagent 4‐cynao‐4‐(phenylcarbonothioylthio)pentanoic acid. Based on these reactions, a well‐controlled reversible degenerative radical polymerization of methacrylate has been demonstrated 29 . Very recently, DPAB as a photoredox catalyst was also successfully used in synthesis of α , ω ‐dithiol and α , ω ‐divinyl telechelic polythioether oligomers through thiol‐ene click polymerization of 1,4‐benzenedimethane (BDMT) and diethylene glycol divinyl ether (DEGVE) 30…”

Section: Introductionmentioning

confidence: 99%

Surface engineering of Si wafers with tunable surface morphology and stiffness via visible light induced thiol‐ene click polymerization with 4‐(N,N‐diphenylamino)benzaldehyde as an organocatalyst

Liao

Fan

J of Applied Polymer Sci

et al. 2022

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A facile strategy is developed to fabricate a two‐layer grafted polymer coatings on silicon wafers, specifically soft crosslinked polythioether as middle damping layer and stiff poly(methyl methacrylate) (PMMA) as top protecting layer. At first, a highly crosslinked polythioether layer was constructed on the surface of the silicon wafer with tunable thickness and smooth morphology with trimethylolpropane tris(2‐mercaptoacetate) and pentaerythritol triallyl ether as monomers and 4‐(N,N‐diphenyl‐amino)benzaldehyde as an organocatalyst. The Young's modulus of the grafted crosslinked polythioether layer is about 300–400 MPa and the roughness is about 11.3 nm measured by atomic force microscope. There are about 9000 ea reactive –SH in a cuboid cell with 1 nm2 base area and 7–14 μm height in the grafted crosslinked polythiolether layer. Then, a flatten PMMA coating layer with Young's modulus as high as ~2.4 GPa was grafted from/onto the surface of the crosslinked polythiolether with surface –SH groups as initiating or chain transfer sites.

Polythioethers with Controlled α,ω‐End Groups Prepared by Visible Light Induced Thiol–Ene Click Polymerization of Dithiol and Divinyl Ether with 4‐(N,N‐diphenylamino)benzaldehyde as Organocatalyst

Zhang

Macro Chemistry & Physics

et al. 2020

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This study reports a step‐growth click‐polymerization of 1,4‐benzenedimethane (BDMT) and diethylene glycol divinyl ether (DEGVE) with 4‐(N,N‐diphenylamino)‐benzaldehyde (DPAB) as a photoredox catalyst under irradiation of visible light. DPAB exhibits a strong UV–vis absorption at 350 nm and a strong fluorescence emission at 480 nm in anisole. There is a strong fluorescence quenching between BDMT and DPAB. The molecular weight of the polythiolether can be controlled by reaction time and monomer feed ratios. More importantly, α,ω‐dithiol and α,ω‐divinyl telechelic polythiolether oligomers are successfully synthesized by simply changing the molar ratios of BDMT to DEGVE. 1H NMR and MALDI‐TOF MS spectra demonstrate that the oligomers have high end group fidelity. In addition, strong fluorescence is observed when the α,ω‐dithiol terminated polythiolether adds with N‐(1‐pyrenyl) maleimide, indicating that the as‐prepared polythiolether bears reactive thiol end groups. Furthermore, high molecular weight polythiolether are prepared by chain extension with reactive polythiolether oligomers as macro‐monomers. For example, α,ω‐divinyl oligomer (Mn = 2000 g mol−1) could further react with α,ω‐dithiol oligomer (Mn = 2400 g mol−1) to form high molecular weight polythiolether (Mn = 6000 g mol−1).