Oxygen Polymer Coated

Rustmaster is a water-based polymer formulation that prevents corrosion in two different ways. First, the polymer layer that cures in air forms a barrier impenetrable to both oxygen and water vapor. Second, the chemicals in the coating react with the steel surface to produce an interlayer between the metal and the polymer coating. This interlayer is a complex mineral called pyroaurite that contains cations of the form [M1 xZr(OH)2]x+, where... 

It is important to pay attention to the potential role of peroxides created on the surface of plasma-treated, including plasma polymer-coated, TPOs in the formation of durable bonds between the substrate and primer. It has been known for decades that the peroxides formed on the irradiated polymers (by y-ray. X-ray, electron beams, etc.) can be utilized in graft copolymerization of various monomers. This method is known as the peroxide method of radiation copolymerization [27]. The trunk polymer is first irradiated by ionizing radiation in a vacuum or in an inert gas environment. The irradiated polymer is exposed to air or oxygen to convert free radicals to peroxides. Thus created peroxides-containing polymers were used as the initiator of the free radical polymerization of the second monomer. The polymer peroxides are decomposed by heat or by the use of reduction/oxidation accelerator, i.e., peroxides are converted to free radicals. 

Plasma polymer-coated [2B] surfaces showed higher polarization resistance than native and chemically cleaned surfaces. Thus, the corrosion resistance of plasma polymer-coated [2B] was much higher than that of the barrier-type oxides formed after chemical cleaning. Also, as is evident from the higher polarization resistance of the plasma polymers, they are good barriers to water, oxygen, and corrosive species, even under an externally applied potential. The Rp values of the... 

Figure 34.19 Variation of (a) oxygen enrichment factors and (b) air flux constants as a function of plasma polymer coating thickness, perfluro-1-methyldecalin plasma polymer coatings deposited onto porous polysulfone hollow fibers at A 5.35 x 10 J/kg 6.64 X 10 J/kg and 8.05 x 10 J/kg.

Potje-Kamloth, K. Josowicz, M. Vielstich, W. Polymer coated oxygen cathode for methanol fuel cell application. In Fall Meeting of the Electrochemical Society Electrochemical Society Toronto, 1992. 

Chemically modified electrodes resulting from the attachment of quinones, phenantroline, dipyridyl complexes, and N4 complexes, from the development of polymer-coated carbon materials, and from electrodes modified by enzymes have been specifically designed for the electrocatalytic reduction of molecular oxygen (OERR). Carbon materials with immobilized hydroquinone have also been utilized to accelerate the electrochemical oxidation of molecular hydrogen. 

Photocatalytic Polymers. The electrochemical experiments cited above were chosen from a vast body of recent polymer coated electrode work. Likewise the field of polymer supported photoredox catalysts is also broad and has a more extended history. Possibly a common linkage between electrochemical and photochemical catalyses, assisted by polymers, can be traced to oxidation of ascorbic acid (AH2). In 1966 Davidov (20a) found that light exposed, polyacrylonitrile (PAN) containing solutions of AH2 consumed oxygen in a measurably different manner than similar solutions without AH2. (Simple photoabsorption of 02 also occurs). 

In Fig. 19(a), a defect in a polymer coating on a metal substrate is shown. The anodic dissolution in the defect leads to a positive current peak. The intact polymer-coated area shows zero current. A second important situation, a cut edge of coil-coated galvanized steel, is shown in Fig. 19(b). The zinc dissolution leads to a positive peak while the area of oxygen reduction on the cathodically protected steel surface is characterized by a broad negative current peak. The activation, distribution, and passivation of these local anodes and cathodes can now be studied by the SVET as a function of coating compositions. 

In Fig. 22, a potential map of the SKP shows a typical situation during the cathodic undermining of polymer-coated iron. In the presence of oxygen, the electrode potential of the metal-polymer... 

Fig. 27 Potential profiles as measured with SKP on partly delaminated polymer-coated zinc sample after a change of the atmosphere from air to pure nitrogen corrosion time before the change 2710 min corrosion times since change as indicated [83]. The Nernst equations explain the local potentials in the absence of oxygen. (Reprinted with permission.)...

To increase the barrier to oxygen, polymer packaging is coated with impermeable layers of metal or silicate glass. Aluminium, if vacuum deposited, is less than a micron thick. Table 11.4 shows that it reduces the permeability of a PET/ PE composite film by a factor of 10. Such collapsible bags are used inside wine boxes, as a method of increasing the shelf life of the partly consumed wine. 

---