Vapor-phase polymerization

Most commercial processes produce polypropylene by a Hquid-phase slurry process. Hexane or heptane are the most commonly used diluents. However, there are a few examples in which Hquid propylene is used as the diluent. The leading companies involved in propylene processes are Amoco Chemicals (Standard OH, Indiana), El Paso (formerly Dart Industries), Exxon Chemical, Hercules, Hoechst, ICl, Mitsubishi Chemical Industries, Mitsubishi Petrochemical, Mitsui Petrochemical, Mitsui Toatsu, Montedison, Phillips Petroleum, SheU, Solvay, and Sumimoto Chemical. Eastman Kodak has developed and commercialized a Hquid-phase solution process. BASE has developed and commercialized a gas-phase process, and Amoco has developed a vapor-phase polymerization process that has been in commercial operation since early 1980. 

Dainton, F. S., and G. B. B. M. Sutherland Application of infrared analysis to elucidate the mechanism of the boron triflouride catalyzed vapor phase polymerization of isobutene at room temperature. J. Polymer Sci. 4, 37 (1949). 

The addition of nitrogen or water vapor changes the pattern of monomer adsorption, release of sorbed monomer, and the rate of monomer vapor consumption by polymerization considerably, as seen in the similar plots shown in Figures 34.10-34.12. With the addition of water vapor, the hydrophilicity of the porous substrate plays an important role that can be seen in the difference of pressure change observed when reversing the order of exposure to monomer and to water vapor. Namely, the amount of water vapor sorbed by hydrophilic Millipore filter is greater when water vapor is introduced first, whereas hydrophobic polysulfone sorbs more water when relatively more hydrophilic (than polysulfone) 4-vinylpyridine monomer is introduced first. Results shown in Figures 34.11 and 34.12 indicate that excessive water vapor prevents vapor phase polymerization... 

Morita, M. Imamura, S. Tamamura, T. Kogure, O. Murase, K. Dry developable multiplayer resist using direct pattern formation by electron beam-induce vapor-phase polymerization. J. Elec-trochem. Soc. 1984, 131 (3), 653-654. 

Rollings DA et al (2007) Formation and aqueous surface wettability of polysiloxane nanofibers prepared via surface initiated, vapor-phase polymerization of organotrichlor-osilanes. Langmuir 23(10) 5275-5278... 

An alternative to solvent-phase synthesis of CEPs is vapor-phase polymerization (VPP). This route was first used for PAn s in 1998 for the deposition of conducting PAn films on cotton fibers, by impregnating the thread with (NH SjOg oxidant and then exposing the surface to aniline vapor.94 Polyacrylamide films coated with conducting PAn (conductivity ca. 10-5 S cm-1) have been similarly prepared.95... 

Vapor-phase polymerization has been used to create a PEDOT structure into which even delicate biomolecules such as enzymes can be incorporated during the subsequent washing step.37... 

Figure 5.5 TEM picture of dendritic nanostructures of thin films cast from PS-b-P2VP-HAuCl4 after vapor-phase polymerization of pyrrole. (Reprinted with permission from Selvan et al., J. Phys. Chem. B, 1999,103, 7441. Copyright 1999 American Chemical Society.)...

Consider a closed vessel in which selenium is in equilibrium with its vapor. Selenium, in the vapor phase, polymerizes to Se species where i = 1, 2, 3,... 

Chen Y.-S., Li Y, Wang H.-C., and Yang M.-J., Gas sensitivity of a composite of multi-walled carbon nanotubes and polypyrrole prepared by vapor phase polymerization. Carbon, 45, 357-363, 2007. 

FIGURE 5.26 Schematic of electrospinning of PEO nanofiber templates containing FeCh followed by vapor phase polymerization of pyrrole. An SEM image of the resulting PPy-PEO composite nanofibers is shown at top right comer. The scale bar for the image is about 500 nm. (After Nair, S., Natarajan, S., and Kim, S. H. 2005. Macromol. Rapid Commun.y 26,1599. With permission.)... 

S. Bhadra and J. H. Lee, Synthesis of higher soluble nanostructured polyaniUne by vapor-phase polymerization and determination of its crystal structure, J. Appl. Polym. Sci., 114, 331-340 (2009). 

Futhermore, nanofiber scaffold electrodes based on PEDOT for cell stimulation were recently reported by Bolin et al. [87]. Electronically conductive and electrochemically active three-dimensional scaffolds based on electrospun poly(ethylene terephthalate) (PET) nanofibers were prepared. Vapor-phase polymerization was employed to achieve a uniform and conformal coating of poly(3,4-ethylenedioxythiophene) doped with tosylate (PEDOT tosylate) on the nanofibers. The PEDOT coatings had a large impact on the... 

S. Nair, E. Hsiao, and S. H. Kim Fabrication of electrically-conducting nonwoven porous mats of polystyrene-polypyrrole core-shell nanofibers via electrospinning and vapor phase polymerization, J. Mater. Chem., 18, 5155-5161 (2008). 

Parylene Thermoplastics made by vapor-phase polymerization of /7-xylene. Hot /7-xylene vapors are cooled to... 

The two principal methods used for the synthesis of aromatic polyamides are interfacial polymerization and solution polymerization. Vapor-phase polymerization and plasticized melt techniques have also been demonstrated but have not been adopted for practical use. 

Vapor-phase polymerization has been described in the patent literature as an alternative route to aromatic polyamides from aromatic diamines and aromatic diacid chlorides [81]. The reaction is carried out in the gas phase by mixing vapors of the two monomers in the presence of an inert gas. The temperature at the reaction zone has to be higher than the glass transition temperature of the polymer to achieve segmental mobility of the growing polymer chain. 

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