Poly -type polymers, direct

Interactions and electric communication between redox centers are of importance for charge transfer. A Ru complex of poly[2-(2-pyridyl)-bisbenz-imidazole] where the redox centers are coordinated directly to a long-range 7t network has been investigated [36b]. Electron-transfer studies yielded electron diffusion coefficients of over 10 cm s" for the Ru(IIEII) state, at least one order of magnitude higher than for a non-conjugated Ru(bpy)3 type polymers. 

A second approach to enhancing miscibility with styrene-type polymers is to introduce H-bonding groups directly into the polystyrene. This approach has been adopted by Moskala et al. [89] who stated that PCL is miscible with poly(vinyl phenol) which has a hydroxyl group in the aromatic group of polystyrene, i.e. is poly(4-hydroxystyrene) (P4HS) 19. 

Laser ablation of polymers has been known since 1982 [8, 19]. Many aspects of polymer ablation and laser processing, in general, have been described by Bauerle [20]. More recently Lippert and Dickinson [21] reviewed in detail the chemical and spectroscopic aspects of polymer ablation and new directions. Many types of polymers can be laser machined, the most common ones being PI, PMMA, polyethylene (PE), polycarbonate (PC), poly(ethylene terephthalate) (PET) and poly-etheretherketone (PEEK). Other polymers include polytretrafluoroethylene (PTFE), S-U8 resist, other photoresists and acrylics. 

Reactions of this type are quite popular and widely used to introduce hydrophilic and ionogenic groups into linear polymers as well as directly into polymer networks. These reactions include hydrolysis (PAAm, PAAc and their analogs from PAN, PVA from poly (vinyl acetate), oxyethylation and oxymethylation of starch and cellulose, sulfurization, and other reactions. These processes are of industrial importance, well studied and widely reviewed. 

Figure 35. Dynamic change of lifetime in an n-type silicon/polymer (poly(epichlorhydrine-co-elhylenoxide-co-allyl-glycylether plus iodide) junction during a potential sweep. The arrows show the direction of sweep (0.25 V s" ). A shoulder in the accumulation region and a peak in the depletion region of silicon are clearly seen.

In an acetone extract from a neoprene/SBR hose compound, Lattimer et al. [92] distinguished dioctylph-thalate (m/z 390), di(r-octyl)diphenylamine (m/z 393), 1,3,5-tris(3,5-di-f-butyl-4-hydroxybenzyl)-isocyanurate m/z 783), hydrocarbon oil and a paraffin wax (numerous molecular ions in the m/z range of 200-500) by means of FD-MS. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out (Chapter 2). The method of Dinsmore and Smith [257], or a modification thereof, is normally used. Mass spectrometry (and other analytical techniques) is then used to characterise the various rubber fractions. The mass-spectral identification of numerous antioxidants (hindered phenols and aromatic amines, e.g. phenyl-/ -naphthyl-amine, 6-dodecyl-2,2,4-trimethyl-l,2-dihydroquinoline, butylated bisphenol-A, HPPD, poly-TMDQ, di-(t-octyl)diphenylamine) in rubber extracts by means of direct probe EI-MS with programmed heating, has been reported [252]. The main problem reported consisted of the numerous ions arising from hydrocarbon oil in the recipe. In older work, mass spectrometry has been used to qualitatively identify volatile AOs in sheet samples of SBR and rubber-type vulcanisates after extraction of the polymer with acetone [51,246]. 

Recently, two new poly(3HB) depolymerase sequences from A. faecalis AE122 and from P. stutzeri were published which contain two instead of only one poly(3HB)-binding domain [57, 64]. Two types of poly(3HB) binding domains can be differentiated by amino acid alignment (types A and B in Fig. 4). Several amino acids are strictly conserved in both types of binding domains. It is not known whether these conserved amino acids are necessary to constitute a particular three-dimensional structure or whether these amino acids are directly involved in the interaction with the polymer chain. 

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