Synthesis direct polymerization

In the last 50 years, scientists have developed novel polymerization approaches, leading to new polymeric materials and applications, with the pace of new discoveries growing. This chapter provides an overview of this body of research, focusing on reactions involving covalent modification of double bonds to prepare monomers (particularly on the formation of polyols for employment as monomers for polyurethane synthesis), direct polymerization reactions between polyunsaturated acyl groups (eg, Diels-Alder, free radical, metathesis. 

Fairly recently, another method for obtaining polymer materials with uniaxial orientation has been developed. It is the directed polymerization i.e. the synthesis of polymers under conditions at which the material attains instanteneously the oriented structure. The formation of crystals from the macromolecules in an extended conformation occurs in those polymerizing systems simultaneously with polymerization22. ... 

Synthesis of BPSH statistical copolymer (14) via direct polymerization. 

This review will outline the materials requirements for advanced alternative proton exchange membranes for fuel cells, assess recent progress in this area, and provide directions for the development of next-generation materials. The focus will be on the synthesis of polymeric materials that have attached ion conducting groups. State-of-the-art Nation and its commercially available perfluorosulfonic acid relatives will initially be discussed. Other chain-growth co-... 

Figure 31. Synthesis of directly polymerized sulfonated poly(phthalazinone ether sulfone) ...

Marsella, M. J. Maynard, H. D. Grubbs, R. H. Template-directed ringclosing metathesis Synthesis and polymerization of unsaturated crown ether analogs. Angew. Chem. Int. Ed. 1997, 36,1101-1103. 

Direct polymerization of benzene through oxidative coupling yields polytp-phenylene) (PPP) an insoluble polymer of low molecular weight.427-429 Kovacic s original synthesis430 using a Lewis acid-oxidant combination [Eq. (13.81)] is the most widely employed and still the most effective procedure for the synthesis of PPP ... 

As reminded by Lazcano and Miller [181], a possibility for the formation of prebiotic polymers is the spontaneous synthesis of a polymer from high-energy precursors. The direct polymerization of glycine nitrile into polyglycine [182-184] is sluggish, but it is thermodynamically favorable and the possibility of indirect catalytic processes remains to be explored. 

Synthesis and Polymerization of Leuchs Anhydrides. The N-carboxy-a-amino acid anhydrides, referred to as Leuchs anhydrides or as NCAs, are synthesized either from N-alkoxycarbonyl derivatives of a-amino acids or from free amino acids. Cyclization of the amino acid derivative by SOCl2 or similar reagents was described first by Leuchs in 1906, but direct synthesis involves treating the a-amino acid or its hydrochloride with phosgene as shown in Figure 4. This method, commonly termed the Fuchs-Farthing method, is the one that is used most frequently since the N-carboxyanhydride may be freed easily from the carbamyl chloride, isocyanate derivative, and hydrogen chloride by crystallization. 

Fossil based raw materials, mainly oil, gas and occasionally coal, are used almost exclusively for the manufacture of monomers. Plant materials, the so-called renewable resources, have been used earlier and could become more significant once again in the future. Although the plastics in these cases are obtained by direct polymerization of their monomers, the synthesis of the monomers themselves often requires several intermediate steps. The multi-functional multiple intermediate compounds in the plastic synthesis steps cannot be clearly defined as monomers in every case. The poly-con-... 

Fig. 1 Synthesis of polymeric nanoparticles from hydrophobic monomers(s) via the direct miniemulsion process...

Although in many cases products 256 can be directly prepared by Mannich synthesis, the replacement reaction is particularly convenient (l)in the case of primary amines, as it yields a secondary amine derivative hardly obtainable through other synthetic routes, and (2) in the case of arylamincs, as it makes it possible to avoid engaging an activated, reactive, aryl group in the direct Mannich reaction. Moreover, the method is frequently adopted in the synthesis of polymeric substances (Chap. III). 

Liaw DJ and Wang KL. Synthesis and characterization of fluorine containing polyamide derivatives from 2,2-bis[4-(aminophenoxy) phenyl] hexafluoropropane by direct polymerization. J Polym Sci 1996 A34 1209-1215. 

The chemical methods for the preparation of nanomaterial could be categorized as either template-directed or template-free. The template synthesis methods commonly used for the production of one-dimensional nanostructured PANI are further subdivided into hard template (physical template) synthesis and soft template (chemical template) synthesis approach according to the solubility of the templates in the reaction media. Non-template routes for the synthesis of one-dimensional nanostructured PANI such as rapid-mixing reaction method, radiolytic synthesis, interfacial polymerization, and sonochemical synthesis have also been reported [56], Other approaches like combined soft and hard template synthesis are also known. An overview of hard-template, soft-template, and template-free procedures are presented in the following paragraphs. 

An alternative to the polymerization o/vesicles with polymerizable surfactants is the polymerization in vesicles, or vesicle templating, in which a hydrophobic monomer swells the surfactant bilayer and is subsequently polymerized (Fig. 2b). In this case the vesicle is used like a mold that directs the polymerization process, and the surfactant molecules themselves are not incorporated into the final polymer. This is a transcriptive synthesis. The polymeric... 

It is clear that further reaction of the hydrocarbons produced in reaction (3) will produce a more complicated series of aldehydes and nitriles via reactions (1) and (2). In the presence of liquid water, a still more complicated reaction sequence becomes possible. Because of the limitations of space, I shall confine the discussion to the possible production of the components of proteins and nucleic acids. The principle pathways of interest here are the synthesis of carbohydrates from formaldehyde and the formation of amino acids, purines and pyrimidines by reactions involving aqueous solutions of HCN. [Although there have been suggestions that HCN can undergo direct polymerization in the gas phase (Matthews and Moser, 1966 Matthews et al., 1977), this reaction has never been directly observed.]... 

One of the primary factors slowing the growth of functional polymers has been the relative complexity and cost of their preparation. The synthesis of functional polymers is often made difficult because of chemical or phase incompatibilities or antagonisms. This chapter surveys the general methods for functional polj er syntheses. It reviews the scope and limtations of functionalization by direct polymerization (e.g. anionic, cationic, free radical and organometallic methods), as weU as post-polymerization bulk and surface modification of preformed backbones. 

Recently, researchers have foimd successful routes to the formation of highly monodisperse liquid crystalline polymers with well defined structures via direct polymerization of the mesogens -. In particular, anionic polymerization is very attractive and allows synthesis of liquid crystalline polymers with well-defined structures, high stereoregularity, and a uniform chain length. In addition, living anionic polymerization is... 

Tsarevsky has found that hypervalent iodine compounds can be used for the direct azidation of polystyrene and consecutive click-type functionalization [49]. In particular, polystyrene can be directly azidated in 1,2-dichloroethane or chlorobenzene using a combination of trimethylsilyl azide and (diacetoxyiodo)benzene. 2D NMR HMBC spectra indicate that the azido groups are attached to the polymer backbone and also possibly to the aryl pendant groups. Approximately one in every 11 styrene units can be modified by using a ratio of PhI(OAc)2 to trimethylsilyl azide to styrene units of 1 2.1 1 at 0 °C for 4 h followed by heating to 50 °C for 2 h in chlorobenzene. The azidated polymers have been further used as backbone precursors in the synthesis of polymeric brushes with hydrophilic side chains via a copper-catalyzed click reaction with poly(ethylene oxide) monomethyl ether 4-pentynoate [49],... 

Among the mentioned techniques, nanogel synthesis in water via direct polymerization of monomer is obviously advantageous because such a process uses water as the dispersant. However, this... 

The understanding of the mechanisms involved in the polymer synthesis with natural precursors is definitively a key factor for their appropriate exploitation. Taking into account this need, Ronda et al. explained recently different pathways to modify natural resources. These authors proposed three routes to modify vegetable oils to transform them into polymers (1) direct polymerization (cationic, radical, or thermal polymerization) (2) functionalization and polymerization and (3) monomer synthesized, chemical modification and polymerization [32]. 

Recent efforts in the synthesis of sulfonated aromatic polymers are directed to the polymerization of sulfonated monomers (such as (b), (d), (g), (j), (k), and (1) shown in Scheme 3) [14,15,53,54,96-102] or coupling reactions of sulfonated compoimds with fimctional groups attached to a polymer backbone [ 103,104]. In post-sulfonation, attachment of the sulfonic acid group is restricted to the activated position ortho to the aromatic ether bond, as indicated in Scheme 4a, while in direct polymerization of sulfonated monomers, the sulfonic acid groups are attached to the deactivated site on the ring (Scheme 4b). An enhancement of stabUity toward desulfonation and a modestly higher acidity are expected for the structure shown in Scheme 4b. Recently, polymerization of sulfonated monomers was also used to obtain sulfonated polysulfone (m) via oxidation of a sulfonated polysulfide-polysulfone copolymer [105]. 

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