Polystyrene/poly-4-vinylpyridine

Partial hydrogenation of acetylenic compounds bearing a functional group such as a double bond has also been studied in relation to the preparation of important vitamins and fragrances. For example, selective hydrogenation of the triple bond of acetylenic alcohols and the double bond of olefin alcohols (linalol, isophytol) was performed with Pd colloids, as well as with bimetallic nanoparticles Pd/Au, Pd/Pt or Pd/Zn stabilized by a block copolymer (polystyrene-poly-4-vinylpyridine) (Scheme 9.8). The best activity (TOF 49.2 s 1) and selectivity (>99.5%) were obtained in toluene with Pd/Pt bimetallic catalyst due to the influence of the modifying metal [87, 88]. 

Antonietti, M., S. Heinz, M. Schmidt, and C. Rosenauer. 1994. Determination of the micelle architecture of polystyrene/poly(4-vinylpyridine) block copolymers in dilute solutiMHcromolecule 7 3276-3281. 

Fig. 18. Th-FFF measurements of polystyrene-poly-4-vinylpyridine (PS123-b-P4VP118) micelles in toluene [216]. The core consists of poly(4-vinylpyridine) which can be used as a nanoreactor for Au synthesis to generate a significantly different Dj- of the core. However, the detected DT is that of polystyrene...

More recently, Dai and coworkers successfully prepared ordered mesoporous carbon films with open-framework structures by using resorcinol and formaldehyde as carbon sources and diblock copolymer polystyrene-poly(4-vinylpyridine) (PS-P4VP) as a template [72]. Similar results were reported by Tanaka et al. [73], in which the same carbon precursor and triblock copolymer F127 (EO106PO70EO106) were used for organic-organic self-assembly. Triethyl... 

Also triblock terpolymers have been studied in solution by several groups [214-216]. Gohy et al. described a system with the sequence of polystyrene, poly(4-vinylpyridine), poly(ethylene oxide). 

Fig. 7. Data of Parsonage et al. [77] on the adsorption of a series of block copolymers of polystyrene-poly-2-vinylpyridine. The ordinate is the measured surface density ( d 2) reduced by the density required for the nonadsorbing chains to overlap the abscissa is the solvent-enhanced size asymmetry of the block copolymer defined under Eq. 26. The form of this plot is that suggested by Eq. 28...

Boron trifluoride-diethyl ether complex is a very versatile and useful Lewis acid in several organic reactions. The polymeric ether-BFs complex poly(p-methoxystyrene)-BF3 (14) has been prepared and is more stable and has higher activity in several organic reactions such as isomerization and epoxide rearrangement [26]. The polymeric version of pyridine-BF3 complex 15 has also been prepared from poly(vinylpyridine) and BF3 [27]. By analogy with the polystyrene-AlCls complex, simple crosslinked polystyrene also forms a stable complex in chloroform with boron trifluoride 16 [27]. 

Pyrolysis of poly(4-vinyl pyridine) was demonstrated to be a free radical process. Both poly(vinyl pyridines) generate as a main pyrolysis product the monomer, 2-ethenylpyridine or 4-ethenylpyridine, respectively. In the pyrogram of poly(2-vinyl pyridine), the dimer is also present (30% of the peak area). This peak is not seen in the pyrogram of poly(4-vinyl pyridine), but it is possible that the compound exists and elutes at a longer retention time than the one used in the chromatographic conditions applied for the pyrolysate separation. Other pyrolysate components not shown in Table 6.5.11 or 6.5.13 were reported in literature. Among these are propenylpyridine, isopropyl-pyridine, isoquinoline, phenylpyridine, 4,4 -dipyridyl, 4-[2-(4-pyridyl)ethyl]pyridine, 4-[2-(4-pyridyl)ethenyl]pyridine, 4-[3-(4-pyridyl)propyl]pyridine, etc. [39]. Similarly to the case of polystyrene, the H-T polymerization is prevalent in poly(vinylpyridine). However, some H-H units can be present in the polymer, and their abundance can be estimated from Py-GC/MS data. 

Radiation-induced Degradation.—There have been several reports on radiation effects in polymers,288 including single crystals,287 fluoropolymers,288 polyamides,289 polysiloxanes,270 polyethylene and its copolymers,271 polypropylene,272 polyolefins,273 polystyrene and its copolymers,274 poly(vinyl chloride) and related polymers,275 rubbers,278 polysulphones and other sulphur-containing polymers,277 polycarbonate,278 nylon,279 poly(vinylpyridines),280 and wool.281... 

The complexation of amphiphilic molecules with functionalized polymers forms layered smectic structures [94-97]. Polymeric complexes 41 consisting of poly(vinylpyridine) and an alkylphenol also form layered organized mesophases [94]. The incorporation of this structure into block copolymers with polystyrene results in the self-organization in two length scales, that is, block copolymer length and nanoscale length [95, 96]. 

Control over the side-chain molecular weight was achieved through the amount of monomer added to the activated substrates. The B values obtained ranged from 1.1 to 1.3 for molecular weights (M ) reaching 7 X 10 g/mol. The same technique was also used to synthesize arborescent copolymers, by adding other monomers in the last side-chain growth cycle, namely, arborescent polystyrene- -poly(fert-butyl methacrylate) and polystyrene- -[polystyrene-fe-poly(2-vinylpyridine)] copolymers [115]. 

This approach is comparatively widely used, for example to evaluate the formation constants of Cu(II) and Ni(II) complexes with polyethylene-grafted-poly(acrylic acid) (PE-gr-PAA) (Table 3-2), Mn(II)-poly(acrylic acid), for studying sorption of low molecular weight compounds by polymers and complexation with modified silica, etc. [35-37]. It was found that one third of the carboxylic groups failed to react with copper ions in the PE-gr-PAA-Cu(II)-system K = 300 L mor, /n,ax = 0.35). For Cu(II) complexes with polystyrene-grafted-poly(vinylpyridine) of different types the values of K andy],. vary from -2500 to 9100 L moL and -0.15 to 0.37, respectively [38]. 

The second example concerns the multidisciplinary study of the micelliz-ing block copolymer polystyrene-( -poly(2-vinylpyridine)-ft-poly(ethylene oxide) (PS-PVP-PEO), which shows a high tendency to aggregation and the formation of micellar clusters [88,89]. It shows the application of SRM for studying the mobility and structural details of different domains in micelle-like polymeric nanoparticles. The fluorescence technique reveals interesting features of studied systems that are hardly accessible by other techniques. Section 3.3 is devoted to the development of the methodology of the solvent relaxation technique for studying nanostructured self-assembling systems. 

Scheme 17.20 Synthesis of polystyrene-poly(2-vinylpyridine) (PS-P2VP)-based polymer catenane 67.

Polystyrene-b-poly(vinylpyridine) with a molar mass of lOOOOgmol" was synthesized by the lithium naphthalide-initiated sequential polymerization of styrene and 2-vinylpyridine, followed by end-to-end intramolecular coupling with l,4-bis(bromomethylbenzene) in THF. The block copolymer was finally purified by predpitation-extraction procedures. 

The solution of polystyrene-block-poly-4-vinylpyridine, which forms hexagonal ordered structures by evaporation, has been mixed with the colloid gold in the thiol. Gold particles prefer to be placed in the crown of polystyrene. If the precursor of FeCls built poly-vinylpyridine domains is subjected to oxidation, then Fc203 nanoparticles built into the PVP core are formed, and the whole nanocomposite acquires the shape of superlattice [348]. 

L. Cui, Y.C. Han, Honeycomb pattern formation via polystyrene/poly(2-vinylpyridine) phase separation, Langmuir 21 (2005) 11085-11091. 

Finally, composition gradients from two different polymer chains have also been used to study wettability effects. A polystyrene poly(2-vinylpyridine) gradient allows a switchable wettability if submitted to a selective solvent treatment. In the selective solvent, one of the two chains collapses and the properties of the surface are determined by mainly the other component. The same effect can be exploited when submitting a polyelectrolyte gradient (poly(tert-butylacrylate) vs. poly(2-vinylpyridine)) to a pH change, Fig. 19. 

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