Polyimide coating

Aromatic polyimides have many anisotropic imide rings and benzene rings, and they are easy to orient by a film-forming process. Molecular orientation in polyimide films causes in-plane/out-of-plane birefringence (AnJ. Russell et al. have reported the A/ / of conventional PMDA/ODA. On the other hand, spin-coated polyimide films just after preparation do not cause Ann, as noted in the... 

A recently reported alternative to spin or spray coating is screen printing of polyimide solutions (82, 85, 90). Screen printing is a low-cost, high-throughput process capable of directly patterning the polyimide films as they are deposited. Another alternative is the vapor deposition of polyimides, which was reported by researchers who co-evaporated the diamine and dianhydride monomers at stoichiometric rates (140). The evaporated films had better adhesion, a lower dielectric constant, and a lower dissipation factor compared with spin-coated polyimides. With this process, uniform, defect-free, conformal films can be cured in situ during deposition. 

Fabrics coated with FEP and PFA can be laminated and heat-sealed into protective garments, canopies, etc. FEP-coated polyimide films are used in electronics and as a wire tape. FEP-based anticorrosion coatings are used in the chemical industry and as chemical barriers.18 A thin coating of FEP or PFA can be used as a hot melt adhesive for a variety of substrates, including PTFE-coated fabrics and laminates. 

M. Tagawa, M. Matsushita, M. Umeno and N. Ohinae, Laboratory Studies of Atomic-Oxygen Reactions on Spin-Coated Polyimide Films, Proceedings of the 6th International Symposium on Materials in a Space Environment, Noordwijk, The Netherlands, 19-23 September 1994, ESA SpeciaJ Pubhca-tion 368, Ed. T. D. Guyenne (European Space Agency, Paris, Prance, 1994) p. 189. 

Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of NOx and SOx Uses Epoxy resin curing agent for prepregs/composites, castings, chem. resist, coatings, polyimide resins, elec, adhesives, high temp. elec, varnishes Manuf./Distrib. Aldrich http //www.sigma-aldrich.com, BASF http //www.basf.com, Schweizerhall http //www.susinc.com Trade Name Synonyms Ancamine 33S t[Air Prods./Perf. Chems. 

Table 1 contains the elemental compositional results obtained by ESCA for Cu coated polyimide films before and after T H exposure. As shown, the metal diffuses into the polymer matrix after the T H exposure. The same result was obtained for Ni. The diffusion of Cu into PI-5878 surfaces detected in our ESCA results correlates with the 4X increase in peel strength (after 500 hours at T H - 85 C 80%) measured (4) for thick Cu films deposited onto cured PI-5878... 

X-ray photons can enter the cryostat and reach the Si(Li) crystal through a thin beryllium window of typically 5-10 pm thickness. The vacuum enclosure protects the detector from surface contamination and moisture condensation (at LN2 temperatures), light and scattered electrons (in electron microprobes). For measuring very low energy/long-wavelength X-rays, the beryllium window can be replaced by ultrathin diamond or aluminum coated polyimide windows or (in vacuum instruments) removed completely. 

Typical water vapor permeation curves are shown in Figure 10-5 (Tohge, 1996). This figure is for uncoated and 40CH3Si03/2-60Si02 coated polyimide (Kapton ) films. The ordinate indicates the increase in pressure due to water vapor permeation through the films and the abscissa indicates the time after the introduction of water vapor to the cell. Both curves increase almost linearly with time, after an introduction period which varies from film to film. The slope of the linear part of the curve (dp/dt) gives a measure of the water... 

Lee JR, Kim NY, Lee MS, Lee SY (2011) Si02-coated polyimide nonwoven/Nafion composite membranes for proton exchange membrane fuel cells. J Membr Sci 367(1-2) 265-272... 

For gas separation hollow fibers, there have been a few systematic studies on the effect of spinning parameters on both the macroscopic dimensions and permeation performance. One paper studies silicone rubber coated polyimide hollow fibres (Chung et al., 1992), another silicone rubber... 

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