Fluoroalkyl methacrylates

In optical applications, in addition to optical liber claddings, special optical adhesives matching refractive indexes of optical glass components based on fluorinated epoxyacrylates and epoxymethacrylates are used.29 Fluoroalkyl methacrylates are frequently incorporated as comonomers with siloxanyl methacrylates into contact lenses for the improvement of oxygen permeability.31... 

Of a large number of possible fluorinated acrylates, the homopolymers and copolymers of fluoroalkyl acrylates and methacrylates are the most suitable for practical applications. They are used in the manufacture of plastic lightguides (optical fibers) resists water-, oil-, and dirt-repellent coatings and other advanced applications [14]. Several rather complex methods to prepare the a-fluoroalkyl monomers (e.g., a-phenyl fluoroacrylates, a-(trifluoromethyl) acrylic and its esters, esters of perfluoromethacrylic acid) exist and are discussed in some detail in [14]. Generally, a-fluoroacrylates polymerize more readily than corresponding nonfluorinated acrylates and methacrylates, mostly by free radical mechanism [15], Copolymerization of fluoroacrylates has been carried out in bulk, solution, or emulsion initiated with peroxides, azobisisobutyronitrile, or y-irradiation [16]. Fluoroalkyl methacrylates and acrylates also polymerize by anionic mechanism, but the polymerization rates are considerably slower than those of radical polymerization [17]. 

ABS polymers terminated with HD-AO moiety RS- were prepared by means of polymerization of butadiene, styrene and acrylonitrile in the presence of tert-dodecylmercaptan [70]. Syner m with phenolic AO was observed. A radical copolymer active as a thermostabilizer for fluoroalkyl methacrylates [71], was prepared from methyl methacrylate (MMA), 2,2,2-trifluoroethyl methacrylate and pentaerythritol tetrakisfthioglycolate). 

The next sequence calls for the coating of a thin layer of a hydrophiUc polymer from an appropriate solvent on top of the photoresist. The polymeric HOL must have a lower glass transition temperature (7g) than the photoresist polymer it must be able to diffuse into the photoresist polymer on baking and it must be phase compatible with the photoresist polymer. Suitable hydrophilic polymers include, but are not limited to, polymers and copolymers of fluoroalkyl methacrylic acid, fluoroalkyl acrylic acid, etc. Surfactants may be used to improve the wettability of the HOL over the resist polymer layer. 

Hence, conformation properties of fluoroalkylmethacrylates molecules define their specific behaviour in the condensed state. Large dipole moment of n-fluoroalkyl methacrylates molecules, as well as their affinity to associate in the condensed state are apparently, the determining factors in growth of polymerisation rate constants of these polymers comparing with alkyl acrylates analogous by structure [56, 57]. 

It was also shown [52] that at radical homopolymerisation of monomers from the fluoroalkyl methacrylic sequence in mixture conversion of the autoacceleration onset increases, and intensity of the gel-effect display decreases as the length of fluoroalkyl radical of the monomer increases. 

Radical polymerisation of fluoroalkyl methacrylates CH2=C(CH3)COOCH2-(CF2-CF2) ,-R, where R = H (I) or CH3 (II), m = 1,2, 3, in the presence of stable iminoxyl radicals was studied [76]. Study of the induction stage indicates that secondary inhibition observed is performed by the catalytic mechanism without using the secondary inhibitor effects... 

The list of fluorine-containing carbochain polymers [24,49,73, 84, 85] can be broadened by synthesising new fluoroalkyl methacrylates with a nontraditional structure of alcohol... 

LI1 Liu, C., He, J., Zhao, Q., Zhang, M., and Ni, P., Well-defined poly[(dimethylamimo)ethyl methaciylate]-6-poly(fluoroalkyl methacrylate) diblock copolymers Effects of different fiuoroalkyl groups on the solution properties, J. Polym. Sci. Part A Polym. Chem., 47, 2702, 2009. 

Mishima, S. and Nakagawa, T. 2000. Sorption and diffusion of volatile organic compounds in fluoroalkyl methacrylate-grafted PDMS membrane.. 7. Annl. Polvm. Sci. 75 773-783. 

Novel surface-active macromonomers were prepared via a two-step synthesis shown in Figs. 13 and 14 [47-49]. Hydrophobic alkyl methacrylate or, as shown in Fig. 13, fluoroalkyl methacrylate monomers were dissolved in a mutual solvent along with a polyoxyethylene methacrylate, a functional mercaptan, and free radically copolymerized. Utilizing the hydroxyl or carboxylate functionality of the end group, the copolymer was then rendered polymerizable by reaction with an appropriate methacrylate-containing reactant as shown in Fig. 14. 

HCL Oxygen-permeable HCL (RGPL) Oxygen-permeable RGPL Highly oxygen-permeable RGPL Cellulose acetate butylate (CAB) Copolymers mainly from siloxanyl methacrylate (SiMA) and MAA Other Copolymers mainly from SiMA and fluoroalkyl methacrylate (FMA) Other... 

Figure 6. Kinetic curves of fluoroalkyl methacrylate diffusion into DEGBAC matrix at different temperatures 1 - 60°C 2 - 40°C 3 - 20°C.

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