Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Vinyl polymers synthesis

Radical polymerization is the most useful method for a large-scale preparation of various kinds of vinyl polymers. More than 70 % of vinyl polymers (i. e. more than 50 % of all plastics) are produced by the radical polymerization process industrially, because this method has a large number of advantages arising from the characteristics of intermediate free-radicals for vinyl polymer synthesis beyond ionic and coordination polymerizations, e.g., high polymerization and copolymerization reactivities of many varieties of vinyl monomers, especially of the monomers with polar and unprotected functional groups, a simple procedure for polymerizations, excellent reproducibility of the polymerization reaction due to tolerance to impurities, facile prediction of the polymerization reactions from the accumulated data of the elementary reaction mechanisms and of the monomer structure-reactivity relationships, utilization of water as a reaction medium, and so on. [Pg.75]

Carbazole, 2-hydroxy-reactions with citral, 4, 235 Carbazole, 2-hydroxy-9-methyl-synthesis, 4, 294 Carbazole, N-hydroxymethyl-as metabolite of carbazole, 1, 230 Carbazole, N-isopropyl-PE spectroscopy, 4, 190 Carbazole, A7-methyl- N NMR, 4, 175 X-ray spectroscopy, 4, 163 Carbazole, 1-nitro-synthesis, 4, 282 Carbazole, tetrahydro-dehydrogenation, 4, 282, 312 synthesis, 4, 107, 337, 353 Carbazole, 1,2,3,4-tetrahydro-reduction, 4, 255, 256 synthesis, 4, 312, 325, 352 Carbazole, 1,2,3,4-tetrahydro-1 -oxo-synthesis, 4, 337 Carbazole, 9-trifluoroacetyl-synthesis, 4, 218 Carbazole, vinyl-polymers, 1, 275, 301 Carbazole, 9-vinyl-copolymer... [Pg.574]

Imidazole-5-carboxamide, l-methyl-4-nitro-mass spectra, 5, 359 Imidazole-4-carboxanilide, 1-methyl-synthesis, 5, 435 Imidazolecarboxylic acid, vinyl-polymers, 1, 281 Imidazole-2-carboxylic acid chlorination, 5, 398 mass spectra, 5, 360 synthesis, 5, 474... [Pg.655]

Pyrazine, tetrahydro-, 3, 177, 178 Pyrazine, 1,2,3,4-tetrahydro-synthesis, 3, 177 Pyrazine, 2,3,5-tri-t-butyl-synthesis, 3, 185 Pyrazine, 2,3,5-trichloro-nucleophilic substitution, 3, 176 Pyrazine, 2-vinyl-polymers, 1, 290-291 Pyrazine-3-carboxylic acid, 2-amino-methyl ester... [Pg.769]

Quinoline, 2,2,4-trimethyl-1,2-dihydro-antioxidant in polymers, 1, 395 Doebner-von Miller synthesis, 2, 468 Quinoline, trimethylstannyl-reactions, 2, 364 Quinoline, 4-vinyl-polymers, 1, 286... [Pg.830]

Photoinitiators provide a convenient route for synthesizing vinyl polymers with a variety of different reactive end groups. Under suitable conditions, and in the presence of a vinyl monomer, a block AB or ABA copolymer can be produced which would otherwise be difficult or impossible to produce by another polymerization method. Moreover, synthesis of block copolymers by this route is much more versatile than those based on anionic polymerization, since a wider range of a monomers can be incorporated into the blocks. [Pg.244]

Because of the great differences in the properties between vinyl polymers and heterochain polymers, copolymerization of a vinyl monomer and a cyclic monomer seems very intersting. Yet, little success has been achieved in the formation of random copolymers because the reactivities are very different between vinyl monomers and cyclic monomers. However, recent progress in the field of organic chemistry has suggested many possibilities especially for the activation of monomers and for the modification of the reactivity of the propagating species. The probability of successful synthesis of random copolymers has thus greatly increased. [Pg.37]

Enzymes are generally classified into six groups. Table 1 shows typical polymers produced with catalysis by respective enzymes. The target macromolecules for the enzymatic polymerization have been polysaccharides, poly(amino acid)s, polyesters, polycarbonates, phenolic polymers, poly(aniline)s, vinyl polymers, etc. In the standpoint of potential industrial applications, this chapter deals with recent topics on enzymatic synthesis of polyesters and phenolic polymers by using enzymes as catalyst. [Pg.206]

Organic Network Formers. As indicated above, an additional organic network can be built up by organic polymer synthesis within an inorganic network. The basic principles are shown in Equations 3 to 5 with a vinyl, methyl methacrylate and epoxide polymerization ... [Pg.335]

The binders vary quite widely—the most common being starch, soy protein and latexes in conjunction with other soluble polymers. Styrene-butadiene latexes have been the most popular but ethylene-vinyl acetate binders are also used. The method of polymer synthesis provides a way of modifying the properties of the latex. For example, adjustment of the ratio of styrene butadiene in the co-polymer gives rise to different degrees of softness or hardness. This property has a profound influence on the quality of the coating. It is also possible to co-polymerise monomers so as to introduce, for example, carboxy groups on to the surface of the latex particle which in turn assist in... [Pg.150]

This chapter will focus exclusively on cross-linked vinyl polymer supports either in a spherical bead or resin form, or in some other macroscopic format. These essentially insoluble materials lead to considerably simplified reaction work-up and product isolation procedures when used e.g. in solid phase synthesis or as catalyst or... [Pg.1]

Fig. 1.7 Synthesis of branched vinyl polymer using a divinyl comonomer and balancing level of thiol-free radical transfer agent - the Cross-linker/ Transfer Method (CTM). Fig. 1.7 Synthesis of branched vinyl polymer using a divinyl comonomer and balancing level of thiol-free radical transfer agent - the Cross-linker/ Transfer Method (CTM).
Uses Demulsifier dye-leveling agent stabilizer for natural oils and vinyl polymers organic synthesis. [Pg.610]

Product Identification was by GC/MS, NMR, and IR. Fundamental crosslinking chemistry was explored using swell measurements on simple solution copolymers and swell and tensile measurements with vinyl acetate (VAc), vinyl acetate/butyl acrylate (VAc/BA) or vinyl acetate/ethylene (VAE) emulsion copolymers. Polymer synthesis 1s described In a subsequent paper (6). Homopolymer Tg was measured by DSC on a sample polymerized In Isopropanol. Mechanistic studies were done 1n solution, usually at room temperature, with 1, 2 and the acetyl analogs 1, 2 (R =CH3). [Pg.454]

The only report on chemoenzymatic synthesis of branched polymers is from Peelers et al. [58], Heterotelechelic PCL macroinimer was synthesized in a one-pot enzymatic procedure by using 2-hydroxyethyl a-bromoisobutyrate as a bifunctional initiator. A polymerizable endgroup was introduced by subsequent in sim enzymatic acrylation with vinyl acrylate. Synthesis of branched polymers by self-condensing ATRP of the macroinimers was successfully conducted with and without the addition of MMA as a comonomer. [Pg.95]

The mechanical synthesis of block and graft copolymers by vibromilling a polymer-monomer blend has been performed by many researchers. Natural polymers (14,17) vinyl polymers (18—27), and heterochain polymers (18, 28-34) have been formed during polymer mechanochemical degradation. Importantly, Simionescu, Vasiliu-Oprea and Neguleanu studied the possibility of carrying out mechanically-induced polycondensations starting from polyesters and diamines (33,35-37). [Pg.8]

Vinyl Polymers. Vibromilling of a vinyl polymer in the presence of a polymerizable monomer can yield both graft and block copolymers. A typical example is the graft synthesis caused by vibromilling poly(methyl methacrylate) in the presence of gaseous vinyl chloride at 25° C for 12 h (19-21,38). [Pg.9]

Polyacetals. Simionescu and coworkers (28) have extended to polyoxy-methylene the process of grafting vinyl polymers (acrylonitrile and methylmethacrylate). They performed the synthesis using a virbomill at room temperature under vacuum (10.1 Torr). The initial monomer-polymer ratio was 1 -5/1.0 and the degree of vibromill packing 0.44. Before milling the polyoxymethylene granules were dissolved in dimethyl formamide and repredpitated with the aim of stabilizer removal and for reduction of polymer particle size (from 2-2.5 mm to 0.05-0.10 mm). Full details of the reaction have been described (40). [Pg.14]

In addition to the chain reaction, like vinyl polymerizations, electro-lytically step-by-step reactions are also rationally to be applied to polymer synthesis. However, electrochemical reaction is not favorable for such a step-by-step reaction, since a growing polymer chain end must be affected at the electrode at each step of the reaction. Hence, only few peculiar attempts have been found successful. [Pg.390]

In spite of the fact that asymmetric carbon atoms1 are formed in the synthesis of vinyl polymers, head-to-tail linear vinyl polymers showing remarkable optical activity in solution cannot be prepared by the usual polymerization processes unless asymmetry centers are already present in the monomers (6, 13). In fact, by considering the principal types of vinyl polymers prepared up to now, the ideal isotactic macromolecules, having such terminal groups as to render both terminal segments of the macromolecule chemically identical, possess a symmetry plane and therefore the polymers cannot show optical activity they might be considered as a peculiar type of meso compounds. [Pg.395]


See other pages where Vinyl polymers synthesis is mentioned: [Pg.169]    [Pg.169]    [Pg.567]    [Pg.667]    [Pg.669]    [Pg.728]    [Pg.829]    [Pg.739]    [Pg.4]    [Pg.244]    [Pg.2]    [Pg.283]    [Pg.664]    [Pg.666]    [Pg.212]    [Pg.366]    [Pg.487]    [Pg.285]    [Pg.150]    [Pg.116]    [Pg.97]    [Pg.204]    [Pg.32]    [Pg.567]    [Pg.667]    [Pg.669]    [Pg.728]   
See also in sourсe #XX -- [ Pg.1212 ]




SEARCH



Polymer vinyl

Synthesis vinylation

Vinyl synthesis

Vinylic polymers

© 2024 chempedia.info