Photoinitiator ethylene glycol-methacrylate

Figure 1 Schematic representation of the synthesis of defined SPB In the first step, a PS latex is generated, which is then covered by a thin layer of the photoinitiator 2-[p-(2-hydroxy-2-methylpropiophenone)]-ethylene glycol methacrylate (HMEM) in the second step. Photoinitiation in the presence of water-soluble monomers, such as acrylic acid, leads to polyelectrolyte chains grafted onto the surface of the core particles in the third step. Taken with permission from Ballauff, M. Macromol Chem. Phys. 2003, 204, 220. ...

The synthesis of PS core particles by emulsion polymerization and polyelectrolyte brushes by photopolymerization was first reported by Ballauff and co-workers in 1999. Figure 1 displays this route schematically First, nearly monodisperse PS cores are made by conventional emulsion polymerization. Then a thin layer of a suitable photoinitiator is polymerized onto the surface of these cores. The photoinitiator, 2-[p-(2-hydroxy-2-methylpropiophenone)]-ethylene glycol methacrylate... 

Guo et al. [150] described the synthesis and characterization of latex particles consisting of a PS core and a shell of linear PAA chains. In the first step, PS cores were covered by a thin layer of a photoinitiator 2-[p-(2-hydroxy-2-methylpropiophenone)] ethylene glycol-methacrylate (HMEM) by means of a seeded emulsion polymerization process. The polymer formed by HMEM on the surface acted as a photoinitiator in the next step, in which acrylic acid was nsed as a water-soluble monomer. The PAA chains were affixed on the surface by means of an attaching from technique that led to particles with well-defined morphology and narrow size distribntion. 

The CSPs prepared by the molecular imprint technique have also been used for chiral resolution by CEC [98-100]. Lin et al. [91] synthesized L-aromatic amino acid-imprinted polymers using azobisnitriles with either photoinitiators or thermal initiators at temperatures ranging from 4°C to 60° C. Methacrylic acid (MAA) was used as the functional monomer and ethylene glycol dimethacrylate (EDMA) was used as the cross-linker. The resulting polymers were ground and sieved to a particle size less than 10 pm, filled into the capillary columns, and used for enantiomeric separations of some amino acids at different temperatures. The relationships of separation factor and column temperatures were demonstrated to be linear between the logarithm of the separation factors and the inverse of the absolute temperature (Fig. 24). The authors also compared the obtained chiral resolution with the chiral resolution achieved by HPLC and reported the best resolution on CEC. The chromatograms of the chiral resolution of dl-... 

In another report, transparent channels (of width 500-200 pm and depth 50-180 pm) were filled with a photopolymerizable liquid mixture consisting of acrylic acid and 2-hydroxyl methacrylate (1 4 molar ratio), ethylene glycol dimethacrylate (1 wt%), and a photoinitiator (3 wt% Irgacure 651 or 2,2-dimethoxy-2-phenylacetophenone). Polymerization was completed in less than 20 s to produce the hydrogel structures [221]. 

A comparison was made of the activity of xanthene dyes as free-radical polymerization photoinitiators that included succinylfluorescein and some of its halogenated derivatives as well as an ester of Eosin with an orrAo-benzoyl-a.-oxooxime group (shown below) under different experimental conditions. The polymerization studies were carried out on 2-hydroxyetiiyl methacrylate with ethylene glycol dimethacrylate as cross linkers using visible light irradiation. N,N,- dimethylaniline was the co-initiator. The polymerization rate obtained with xanthene dyes was found to be similar to or as much as 4.5 times higher (in the case of the Eosin ester) than that reached with Eosin alone. ... 

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