Polymerizations light induced

The basic principle of the light-induced polymerization of multifunctional monomers can be represented schematically as follows ... 

This polymer contains carboxylic as well as acrylic functionality. The acrylic part of the polymer undergoes light induced polymerization. Use of this photoreactive polymer eliminated the need for separate acrylic type polymerizable monomer(s). 

A kinetic model for single-phase polymerizations— that is, reactions where because of the similarity of structure the polymer grows as a solid-state solution in the monomer crystal without phase separation—has been proposed by Baughman [294] to explain the experimental behavior observed in the temperature- or light-induced polymerization of substimted diacetylenes R—C=C—C=C—R. The basic feature of the model is that the rate constant for nucleation is assumed to depend on the fraction of converted monomer x(f) and is not constant like it is assumed in the Avrami model discussed above. The rate of the solid-state polymerization is given by... 

The anthocyanidins are unstable and very prone to oxidation and light induced polymerization, hence these precautions. The sample should be analyzed within 60 minor significant degradation may occur in spite of the above precautions. 

A photoinduced carbon-carbon bond formation proceeds within visible light induced polymerization of methyl methacrylate in the presence of A1(TPP)(CH3). The polymerization [115] can be expressed as follows... 

The CAD design generated the geometry by performing Boolean operations on simple volumic primitives [2], The microstructure was realized by microstereolithography. This technique is based on a layer-by-layer light-induced polymerization of a liquid resin, a pre-polymerized solution. Actually, about 1800 layers of 5 pm thickness were superimposed in this way (5 h manufacturing time). 

The traditional [7] kinetic scheme used for the description of light-induced polymerization processes is given by Eqs. (9)-(12). 

Figure 4.30 Light-induced polymerization of cationic choline acrylate counterions on negatively charged vesicle surfaces produces a polymer net around the vesicle. ...

The study of light-induced polymerization of the new compounds, especially CL 1042, demonstrated the outstanding reactivity of acrylic monomers containing five membered cyclic carbonate function (Ref. 52). Photopolymerization even occurs without any added photoinitiator. 

In this paper we report some of the progress recently made in these various areas, concentrating on the light-induced polymerization of multiacrylic monomers which are today the most widely used UV-curable systems. We also describe here a new analytical method, based on IR spectroscopy, that permits the kinetics of photopolymerizations, which develop extensively in a fraction of a second, to be followed quantitatively and in real time. 

It was known as early as the previous century that certain conjugated diacetylenes in the solid state progressively develop an intense colour under normal conditions [16]. These observations were later correctly attributed to thermally Induced or light-induced polymerization of diacetylene units, but the proposed mechanism was false. A correct interpretation of the phenomena was provided only recently (ref. in [15]). 

DOPA-derivatized polymerizable lipids have recently been reported. The diacetylenic monomer VII contains a hydro-phobic polymerizable lipid attached to a DOPA-containing polar head group. Self-assembly of VII into vesicles and light-induced polymerization yielded stable adhesive vesicles, fibrils, and sheets, and the interfacial adhesive behavior of these stmaures was evaluated. 

Figure 5 Influence of the radical-type photoinitiator on the light-induced polymerization of a polyurethane-acrylate resin. Decay curve of the phosphine oxide photoinitiator...

This method is not a versatile technique for the synthesis of ECPs. Light-induced polymerization technique has not attracted the attention of researchers as it is a time-consuming process and the quality of the polymers formed are not up to the standards. 

Decker, C., Morel F., Jonsson, S., Clark, S. and Hoyle, C.E., Light-induced polymerization of photoinitiator-liee vinyl-ether-maleimide systems, Macrotnol. Chem. Phys., 1999, 200, 1005-1013. 

The photopolymer materials shown in Rg. 4.33 contain acrylate and vinyl monomers blended with an oligomer capped with urethane acrylate endgroups (Mn 2000) and 1% by mass photoinitiator for light-induced polymerization. Formulation ACR contained 40 mass% acrylate monomer and 60 mass% ohgomer. In the second formulation, VACR (vinyl monomer-containing polymer), 10% of the acrylate monomer was replaced with a vinyl monomer while the amount of oligomer remained unchanged. Prior DSC studies of ACR and VACR show that the components are miscible and the cured Tg values are 16 C and 26 C, respectively (Bair et al. 1997). 

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