Fluoroalkyl-group polymers

To improve the solvent resistance of the polymer, a fluoroalkyl group can be substituted on each silicon atom for one of the methyl groups, the resultant polymer (ISO designation FMQ or FVMQ) having the following repeat unit. 

The high values for the trifiuoropropyl group are surprising but correspond with the liquid surface tension of polytrifluoropropylmethylsiloxane [13], although not in line with its critical surface tension and solid surface tension. The low values for the longer fluoroalkyl groups are comparable to the lowest surface tension fluoropolymers and correspond well with the values for related preformed fluorosilicone polymers [14-15]. 

As an attempt to Improve the selectivity of oxygen permeation, copolymers with FA, and polymers of fluoroalkyl substituted S2 were synthesized. The results are also shown In Figure 5. Introduction of fluoroalkyl groups, at present, does not Improve the selectivity significant. 

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

Polyphosphazenes with simple alkyl and aryl substituents directly attached to the backbone by P-C linkages can be prepared by the condensation polymerization of N-silylphosphoranimine precursors. These simple polymers can then be converted to a variety of functionalized polyphosphazenes by derivatization reactions. In this paper, the synthesis and characterization of some derivatives of poly(methylphenyl-phosphazene), [Me(Ph)P=N]and the copolymer, [Me(Ph)P=N]j [Me2P=N)y, are discussed. These polymers include grafted copolymers, water soluble carboxylated polymers, and polymers with silyl, vinyl, alcohol, ester, ferrocene, phosphine, thiophene, and/or fluoroalkyl groups. 

The characteristics of fluoropolymers are summarized in Table 1. Thermal and chemical resistance is in general with most of plastics, elastomers and perfluorinated membranes. Weather resistance with the outdoor durability for more than 20 years is specific for fluorinated paint resins. Surface properties such as water and oil repellency are provided by acrylic polymer-based textile finishes and coatings with long-chain per-fluoroalkyl groups. Electrical properties as well as a low refractive index are important for optoelectronics applications like optical fibers. 

Most fluorinated soil retardants are vinyl polymers, urethanes, or oligomers derived from pyromellitates. Numerous fluorinated soil retardants have been disclosed in the patent literature, but only some examples can be given here (Table 13.2). Usually a vinyl polymer consists of (1) a fluoroalkyl group containing monomer [e.g., 2-(perfluorononyl)ethyl acrylate, the methacrylate CH=C(CH3) COOCH2CH2C F2 +i, or CH=C(CH3) C00CH2CH2(CH3) S02(CF2)8F], (2) a nonfluorinated alkyl acrylate or methacrylate (e.g., butyl or stearyl acrylate or methacrylate), and (3) a cross-linkable monomer for durability (e.g. A methylo-... 

The chemical requirements leading to a low dielectric constant (below 3) and low moisture uptake are the same which were discussed in the previous section. Bulky substituents like fluoroalkyl, fluoroalkoxyl,68,69 or cardo70 groups allow the dielectric constant to drop to 2.6-2.7. The moisture uptake is also minimized for these polymers.71 Similar results were observed with cycloaliphatic imides64 but with a lower thermal stability. 

A higher level of incorporation can be achieved by resubjecting the modified polymer to the reaction conditions, as seen in the conversion of sample 6 -> 7. A third exposure to the conditions, which involved the conversion of sample 7 -> 8, does not give higher incorporation, and in fact appears to result in a decrease. Thus the reaction appears to be self-limiting, and the existing fluoroalkanol or fluoroalkyl ether groups may act to quench the radical promoter, and inhibit further incorporation. 

To aid in the characterization of the modified polymer samp os 1-10, and of the mixtures 11 and 12 obtained from functionalizing the two cycloalkanes, we prepared the model fluoroalkanols 13 and 14 as shown in Equation 2 (11-12), and the model fluoroalkyl ethers 15 and 16 as shown in Equation 3 1 3). Compounds 13 and 15 were previously isolated by- the Dupont group (8) from their mixture 11. Products 13-16 proved to be good comparison compounds for the infrared spectra, and particularly- for the 19F-NMR spectra. The I9F-NMR signal for the fluoroalkanol is approximately 1 ppm downfield from that of the fluo-roalky.l ether, which is enough to get semiquantitative ratios of... 

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