Vapour phase polymerization

A limited kinetic investigation of vapour phase polymerization of propene has been reported by Grigor ev et al. [321]. Samples of TiCla prepared by reducing TiCl4 by aluminium and with surface areas of 15.7—27.2 m g" were used. (They contained ca. 4% of Al). Maximum rates occurred at Al/Ti 0.6 to 1.1. It is not possible to apply a monomer concentration term to the data for comparison with results in solution, but at a propene pressure of 1 atm. rates were high at ca. 3—5 x 10" moles/mole Ti/sec. a -TiCl3 with no combined aluminium but of comparable surface area had about half the activity of the aluminium-containing samples. 

Najara, S.S., Kaynak, A., and Foitzik, R.C. (2007) Conductive wool yarns by continuous vapour phase polymerization of pyrrole. Synth. Met., 157,1-4. 

An alternative chemical synthesis mefliod to eonventional solution-based CP deposition is the so-called vapour phase polymerization (VPP) teehnique (Mohammadi et al. 1986 Kim et al. 2003 Wintiier-Jensen and West 2004 Winther-Jensen et al. 2005 Fabretto et al. 2008). There is much interest in this method because it provides high eontrol over CP film thickness, uniformity, and density. Typically, the formation of conjugated polymers is carried out directly on the surface of the substrate in a two-step process. First, fire oxidant such as iron tosylate in n-butanol is applied on the substrate using solvent coating processes and then the coated surface is exposed to a reactive CP monomer vapour. PEDOT films have been reported to have with conductivities as high as approximately 3400 S.cm or S cm for a thickness of 60 mn, which is equivalent to commercially available indium tin oxide (ITO) (Fabretto et al. 2012). 

Co-axial nanoscales of PPy-Ti02 nanocomposite Vapour phase polymerization method [52]... 

Chemistry of polychloroprene rubber. Polychloroprene elastomers are produced by free-radical emulsion polymerization of the 2-chloro-1,3-butadiene monomer. The monomer is prepared by either addition of hydrogen chloride to monovinyl acetylene or by the vapour phase chlorination of butadiene at 290-300°C. This latter process was developed in 1960 and produces a mixture of 3,4-dichlorobut-l-ene and 1,4-dichlorobut-2-ene, which has to be dehydrochlorinated with alkali to produce chloroprene. 

The next study of wood modification was that reported by Baird (1969), who performed vapour-phase reactions of spruce with ethyl, n-butyl, /-butyl, allyl and phenyl isocyanate (PhNCO). Unfortunately, DMF was used as a catalyst for the reactions, which resulted in polymerization of PhNCO in the cell wall of the wood, leading to unpredictable results. No evidence was presented in support of the contention that polymerization had occurred, and since this requires an anionic catalyst initiator, this is considered unlikely. However, the presence of side reactions when DMF is used in conjunction with isocyanates has already been mentioned. Greater success was reported when butyl isocyanate was reacted with wood (presumably a consequence of the lower reactivity of this isocyanate... 

The mono-thiocarbamate complexes [Ni(OSCNR2)2] [R = Me, Et, Pr", Pr , or Bu", R2 = ( 112)4 or (CH2)j] have been prepared. The isopropyl complex is dimeric in the vapour phase and low-polymeric or cyclic oligomeric structures are proposed for the others. Bis-pyridine and bis-pyrrolidine adducts have been isolated. - ... 

Therefore, the appearance of the C—Li bands at unexpected low wavenumbers and their behaviour upon isotopic substitution demonstrate that these bands represent complex modes of vibration in polymeric molecules rather than simple C—Li stretching motions (Figure 1). It is well known that organolithium compounds are strongly associated in solution Furthermore, the C—Li bands occurred in the mulls and solution spectra of ethyllithium at similar positions to those in the vapour spectra, namely in the region from 570 to 340 cm (Table 1) . In benzene solution the bands were found at 560 and 398 cm for CiHs Li and at 538 and 382 cm for CiHs Li. This seems to confirm the previous finding of Berkowitz and coworkers that ethyllithium is polymeric even in the vapour phase. ... 

In their papers Rodionov and coworkers described the polymerization of organolithium compounds in terms of the formation of lithium bonds (Scheme 1), analogous to hydrogen bonds, which brought about cyclic or linear association of these compounds in solution . However, the strong association of alkyllithium compounds, persisting even in the vapour phase, indicates that their association takes place through the formation of... 

V.N. Vasilets, G. Hermel, U. Konig, C. Werner, M. Muller, F. Simon, K. Grundke, Y. Ikada, H.J. Jacobasch, Microw/ave CO2 plasma-initiated vapour phase graft polymerization of acrylic acid onto polytetrafluoroethylene for immobilization of human thrombomodulin. Biomaterials 18 (1997) 1139-1145. 

Disulfur monoxide, S20, can be prepared, along with SO, by the reduction of S02 in a glow discharge or from the reaction of metal sulfides with SOCl2. In the vapour phase at low pressure it slowly decomposes to S and S02 but in condensed phases it polymerizes. Its structure is similar to that of S02 with an SSO bond angle of 1 180.39 43 The complex t(Ph2PCH2CH2PPh2)2Ir(S20)]Cl (9) has been prepared by the reaction shown in equation (l).41 The complex (9) is air stable and the IR spectrum shows only one v(S—O) at 1043 cm-1.41,44 The complex [Mo(S20)(S2CNEt2)2] has also been isolated in small yield.45... 

New photoreactive polymers with dimethylmaleimide side groups have been prepared, "" and co-polymers of methyl methacrylate with oligourethanes have tensile properties superior to those of the separate homopolymer systems."" New monomers have been prepared for fire-retardant u.v.-curable polymers " and trimethylolpropane has been photopolymerized in the vapour phase. Diphenylsulphoniumbis(methoxycarbonyl)methylide photoinitiates the polymerization of styrene and methyl methacrylate through the formation of... 

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