Tetraalkylammonium Salts of Amino Acids and Sulfur‐Containing Amino Acids as Effective Co‐Initiators of Free Radical Polymerization in the Presence of Aromatic Ketones

Ścigalski, Franciszek; Pączkowski, Jerzy

doi:10.1002/macp.200800122

Cited by 14 publications

(6 citation statements)

References 33 publications

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“…Interestingly, the photodecomposition of NPG sensitized by polycyclic aromatic hydrocarbons (e.g., pyrene) was investigated under the irradiation of UV light (366 nm) and can be utilized as a photoinitiating system for the free radical photopolymerization of acrylate monomers . In addition, tetraalkylammonium salts of amino acids and sulfur-containing amino acids have also been reported as effective co-initiators of free radical polymerization in the presence of aromatic ketones . Even though NPG exhibits the UV light absorption, to the best of our knowledge, there is no report on the investigation of its inherent photochemistry and photoinitiation ability of polymerization under near-UV light.…”

Section: Introductionmentioning

confidence: 99%

“…30 In addition, tetraalkylammonium salts of amino acids and sulfur-containing amino acids have also been reported as effective co-initiators of free radical polymerization in the presence of aromatic ketones. 31 Even though NPG exhibits the UV light absorption, to the best of our knowledge, there is no report on the investigation of its inherent photochemistry and photoinitiation ability of polymerization under near-UV light.…”

Section: ■ Introductionmentioning

confidence: 99%

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N-Phenylglycine as a Versatile Photoinitiator under Near-UV LED

et al. 2018

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N-Phenylglycine is normally used as a co-initiator and can be photodecomposed by different dyes under UV or visible light irradiation to generate radicals for the initiation of free radical photopolymerization. However, the photochemistry and photoinitiation ability of N-phenylglycine alone upon exposure to near-UV light (e.g., UV LED at 392 nm), to the best of our knowledge, have not been investigated. In this research, the photochemistry of N-phenylglycine under the UV LED at 392 nm is studied using various approaches, and it reveals that radicals (PhNHCH2 •) can be produced from the direct photodecomposition of N-phenylglycine. In addition, N-phenylglycine can also interact with iodonium salt under the UV LED at 392 nm to generate phenyl radicals and cations. These formed active species exhibit high performance to initiate the free radical photopolymerization of acylates and cationic photopolymerization of epoxides and divinyl ethers.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

N-Phenylglycine as a Versatile Photoinitiator under Near-UV LED

et al. 2018

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“…This behavior may be explained by the relatively higher electronic effect and steric hindrance of the butyl groups. Tetraalkylammonium cations are a particularly useful bridge for facilitating the electron transfer process in photoinduced polymerization reactions [ 38 ]. This process also influences the triplet state lifetime of PBGs.…”

Section: Resultsmentioning

confidence: 99%

Carbanion as a Superbase for Catalyzing Thiol–Epoxy Photopolymerization

Dong

Shen

et al. 2017

Polymers

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Photobase generator (PBG)-mediated thiol-epoxy photopolymerization has received widedspread attention due to its versatility in various applications. Currently, nearly all reported PBGs release amines as active species. The formed amines induce odor, yellowing, and potential toxicity. In this study, a series of novel thioxanthone-based PBGs, which were able to generate carbanion via decarboxylation under LED light irradiation, were designed and straightforwardly prepared. The formed carbanion can be used as a superbase to catalyze thiol-epoxy polymerization efficiently. Investigation on 1 H NMR and FT-IR confirmed the generation of carbanion intermediates. The counteranion significantly affected the photodecarboxylation efficiency. The study of photopolymerization tests, based on real-time FT-IR and dielectric analysis measurements, indicated that the generated carbanion exhibited faster polymerization rate and higher epoxy conversion than traditional superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). In differential scanning calorimeter, thermogravimetric, and nanoindentation tests, comparable thermal and mechanical properties of the photocured films catalyzed by novel PBGs were obtained. The high initiation ability combined with straightforward synthesis makes these PBGs promising candidates for commercialization.

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“…The quantum yields of triplet state formation were determined using methodology given by Waluk et al 57 and by us. 58 The method is based on quantitative analysis of the ground state recovery and its deconvolution that concerns an instrumental response function. Typical example of such approach is shown in Fig.…”

Section: Spectroscopic and Physico-chemical Propertiesmentioning

confidence: 99%