Search

Ionic liquids using amino acid ester as cations is a new generation of green ionic liquids. It is found for the first time that they can be used as co-initiators to initiate radical photopolymerization in the presence of commercial type II sensitizer, camphorquinone (CQ) under mild irradiation conditions. To intensively investigate this new function, we synthesized a series of glycine ester ionic liquids by a very simple method, and then evaluated their performance as co-initiators in radical photopolymerization. The polymerization studies show that their coinitiation abilities depend strongly on the structures of N-terminal substituents and ester groups, as well as the type of anion moiety. And the pH values of the formula also have a heavy influence on their performances. More interestingly, when a small amount of hydroxyethyl acrylate (HEA) was added, under irradiation this multicomponent system composed of CQ, ionic liquids when anion moiety is P[F.sub.6.sup.-1], B[F.sub.4.sup.-1] or Sb[F.sub.6.sup.-1], and HEA, can release [H.sup.+] to initiate cationic polymerization. These facts demonstrated that the investigated glycine ester ionic liquids can be considered as valid, environmentally friendly alternatives to toxic aromatic amines co-initiators. Besides, the corresponding photoinitiation mechanism is suggested. KEYWORDS cationic photopolymerization, glycine ester ionic liquid, initiation system, photoinitiation efficiency, radical photopolymerization, 1 | INTRODUCTION The photopolymerization technique has been widely used in in coating, ink, adhesives, 3D printing materials, optics, medicine, microelectronics, nanotechnology, and so on f11. Radical and cationic photopolymerization [...]

Free radical photopolymerization is an environmentally friendly green production and processing technology and is widely used in the curing of thin samples such as coatings, adhesives, and varnishes. However, for thicker samples or opaque materials, limited light absorption and scattering and reflection from the components of the formulation lead to the failure of polymerization. Dark polymerization is an effective strategy that overcomes these limitations. This paper reviews current developments in the field of photoinduced dark radical polymerization in terms of features of the dark polymerization formulation, developed photoinitiator/initiating systems and active monomers with dark polymerization, and application scope and trends.

Silk peptide used as a co-initiator in type 2 photo-initiator has not been known. In this study, the photoinitiation system is composed of the sensitizer, the synergist and silk peptide with low molecular weight (, INTRODUCTIONIt is well known that free radical photopolymerization is characterized by fast curing rates, low heat release, spatial and temporal control over polymerization and room temperature operation [1]. Therefore, it [...]

Three dye-linked photoinitiators with excellent spectral stability in an acid medium were synthesized by the covalent bonding of a coinitiator (tertiary amine) and a benzoyl group or two coinitiators to the phenolic and carboxyl group position of erythrosine B. The combination of the iodonium salt and free tertiary amino used to initiate the free-radical/cationic visible photopolymerization was investigated to acquire the relationship between the structure and performance. The photoinitiating ability of the derivative with the phenolic position bearing a coinitiator was poorer than of the derivative with the carboxyl group bearing one because of the strong back electron transfer of the former. For the derivative with a linked coinitiator on the carboxyl position, the proximity effect between the sensitizer and the coinitiator moiety resulted in an excellent photoinitiating ability for radical/cationic polymerization; this suggested its potential for application. Although radical/cationic photopolymerization could be initiated by the derivative/coinitiator/iodonium salt, the different component ratios between them had different effects on these two polymerizations; this provided useful information for the design of effective photoinitiators for different polymerizations. On the basis of the fluorescence quenching and photopolymerization results, a corresponding synergistic mechanism was proposed. [ABSTRACT FROM AUTHOR]