Calcium-polymer interface

In the many reports on photoelectron spectroscopy, studies on the interface formation between PPVs and metals, focus mainly on the two most commonly used top electrode metals in polymer light emitting device structures, namely aluminum [55-62] and calcium [62-67]. Other metals studied include chromium [55, 68], gold [69], nickel [69], sodium [70, 71], and rubidium [72], For the cases of nickel, gold, and chromium deposited on top of the polymer surfaces, interactions with the polymers are reported [55, 68]. In the case of the interface between PPV on top of metallic chromium, however, no interaction with the polymer was detected [55]. The results concerning the interaction between chromium and PPV indicates two different effects, namely the polymer-on-metal versus the metal-on-polymer interface formation. Next, the PPV interface formation with aluminum and calcium will be discussed in more detail. 

Theoretical Studies of Metal/Conjugated Polymer Interfaces Aluminum and Calcium Interacting with 7i-Conjugated Systems... 

In some cases, it is desirable to increase the permeability of a polymeric material. One example is breathable films. For example, calcium carbonate filled PP films are first made by solvent casting, or extrusion casting or as blown film and subsequently stretched to delaminate the filler - polymer interface [57]. High filler loadings are used to ensure interconnecting voids, giving unimpeded diffusion [58]. 

Chen HT, Gao J, Wang G, Shi SQ, Zhang SB, Cai LP (2004) Effect on temperature on calcium carbonate deposition in situ on bamboo fiber and polymer interfaces. Wood Fiber Sci 46 1-12 Datta C, Basu D, Baneijee AN (2002) Mechanical and dynamical mechanical properties of jute fibers-Novolac-Epoxy composite laminates. J App Polym Sci 85 2800-2807 Garea SA, Nicolescu A, Deleanu C, lovu H (2010) New nanocomposites based on epoxy resins reinforced with modified montmorillonite. Int J Polym Anal Charact 15 497-508 Ghosh P, Mitra PS, Baneijee AN (2003) Photopolymerization of methyl methacrylate with the use of bromine as photoinitiator. J Polym Sci Polym Chem Ed ll(8) 2021-2030 Jia N, Li SM, Ma MG, Sun RC, Zhu L (2011) Green microwave-assisted synthesis of cellulose/ calcium silicate nanocomposites in ionic liquids and recycled ionic liquids. Caibohydr Res 34 2970-2974... 

Since PVC is less thermally stable than many other polymers, lubricants and thermal stabilizers are always included in PVC formulations. Lubricants are typically oxidized polyethylene waxes, simple 165° melting paraffin waxes that have a range of melt temperatures. Lubricants are used to vary the fusion properties of PVC and to facilitate flow at the metal-polymer interface in the processing equipment. Thermal stabilizers are used to prevent dehydrohalogenation or unzipping of the polymer by loss of HCl which, even at well less than 1% decomposition, results in discoloration. Calcium stearate at low levels acts as an internal lubricant and enhances fusion. At higher levels it acts as an external lubricant. In addition, it has some stabilizer properties, analogous to other metal so s. 

C. Fredriksson and S. Stafstrom, Metal/conjugated polymer interfaces sodium, magnesium, aluminum and calcium on truns-polyacetylene, J. Chem. Phys. /0/ 9137 (1994). 

Since the calcium or other metals used so far as electrodes must be rigorously protected from the atmosphere to prevent degradation further applications have to find stable electrode materials. Also, the attainable electric currents and the efficiency of the polymeric LED depends sensitively on the polymer-electrode interface. 

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