Fluorocarbon polymers, comparison

Surface Protection. The surface properties of fluorosihcones have been studied over a number of years. The CF group has the lowest known intermolecular force of polymer substituents. A study (6) of liquid and solid forms of fluorosihcones has included a comparison to fluorocarbon polymers. The low surface tensions for poly(3,3,3-trifluoropropyl)methylsiloxane and poly(3,3,4,4,5,5,6,6,6-nonafluorohexyl)methylsiloxane both resemble some of the lowest tensions for fluorocarbon polymers, eg, polytetrafluoroethylene. 

Table X. Comparison of PTFPMS with Other Fluorocarbon Polymers...

Ohsaka et al. [393] reported on the preparation by electrochemical oxidation and properties of thin films of 1-naphthylamine in acetonitrile solutions. These films had conductivities of 10 to 10" S cm". Aminocoronene, which consists of seven fused aromatic rings and an amino group, has also been polymerized [394]. Eaves et al. [395] polymerized perfluorocyclopentene in dimethyl formamide in the presence of tetrabutlyammonium perchlorate. The fluorocarbon polymers could exhibit enhanced environmental stability in comparison with hydrocarbon polymers. 

Molecular Structure.—A review has appeared that compares the relationship between polymer structure and surface-active properties of the poly(dimethyl siloxane)s (PDMS) with that of hydrocarbon and fluorocarbon polymer systems." A mathematical study of the spreading of (PDMS) oil drops has been presented and experimental data shown to be in good agreement with predictions. Quantitative comparison of previously published n.m.r. spin-relaxation data for poly(diethyl iloxane)s with theoretical predictions for a variety of motional processes, have allowed both the nature and time scale of molecular motions to be identified."... 

Diamines were the first materials used to cross-link polyacrylates and fluorocarbon polymers. They provide excellent compression set and aging characteristics, but require an oven post-cure after molding to develop optimum properties. These curatives are also corrosive to mild steel molds. See Table 13.10 for a comparison of two diamines and a bisphenol curative in a fluoroelastomer. 

Although to-date the emphasis has been on plasma polymerized films produced from hydrocarbon based systems, this trend in more recent times has swung towards fluorocarbons in an attempt to produce polymers of similar properties to conventionally prepared linear fluoropolymers. However, it will become clear from the account to follow that in many respects plasma polymerized fluorocarbons differ significantly from their linear counterparts. It is to the plasma polymerization of organic monomers containing solely carbon and fluorine therefore that we shall devote our attention in this section with only brief references to hydrocarbon and fluorohydrocarbon polymers for comparison purposes. 

ANG Angelis, M.G.de, Merkel, T.C., Bondar, V.I., Freeman, B.D., Doghieri, F., and Sartim G.C., Hydrocarbon and fluorocarbon solubility and dilation in poly(dimethylsiloxane) comparison of experimental data with predictions of the Sanchez-Lacombe equation of state,/. Polym. Sci. PartB Polym. Phys., 37, 3011, 1999. 

The assignment of resonances was originally based on comparison of the chemical shifts with those for appropriate fluorocarbons. Confirmation has been provided by a procedure involving the preparation of polymers by a method leading to materials with various proportions of inverted monomeric units. Copolymers of CH2. CF2 with low contents of CF2 CHC1 were prepared. The presence of the large chlorine atom in the molecule of the comonomer ensures that it enters the copolymer in such a way that the structure -CH2 CF2 CF2 CHCI CH2 CF2- is produced. The copolymers were treated with tri-n-butyltin hydride so that the comonomer units were converted to those that would be formed by head-to-head addition of a molecule of vinylidene fluoride. 

In general, polymers are much more resistant to attack by acidic and alkaline solutions than are metals. For example, hydrofluoric acid (HF) corrodes many metals as well as etch and dissolve glass, so it is stored in plastic bottles. A qualitative comparison of the behavior of various polymers in these solutions is also presented in Tables 17.4 and 17.5. Materials that exhibit outstanding resistance to attack by both solution types include polytetrafluoroethylene (and other fluorocarbons) and polyetheretherketone. 

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