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Replica polymerization

Polymerization of monomers in the presence of polymem which can interact with monomers or newly formed polymers via secondary binding forces is called matrix polymerization (or template polymerization, replica polymerization) (Fig. 52). It is expected that matrix polymerization fundamentally affects the kinetic behavior and/or controls some structural details (for example, molecular weight and its distribution, tactidties, optical isomerism, etc.). However, a variation of structural details seems to be realized only when the geometry of the monomers firmly bound on the matrix polymers, which exhibit a regular arrangement of their structures, can be controlled. [Pg.103]

The influence of preformed stereoregular polymethylmethacrylate on the polymerization mechanism is particularly interesting. Grignard compounds at — 50 C in toluene give syndiotactic poly(methylmethacrylate) when preformed isotactic poly(methyl-methacrylate) is present, and vice versa [30,31]. In this replica polymerization, the primary structure formed is the 1 1 (isotactic/syndiotactic) complex. Further association between this complex and syndiotactic macromolecules results in the 1 2 (isotactic/syndiotatic) complex [32]. In the absence of preformed polymer, isotactic poly(methylmethacrylate) was obtained under the same conditions. [Pg.690]

Liquori et al. [23] first discovered that isotactic and syndiotactic PMMA chains form a crystalline stereocomplex. A number of authors have since studied this phenomenon [24]. Buter et al. [25,26] reported the formation of an in situ complex during stereospecific replica polymerization of methyl methacrylate in the presence of preformed isotactic or syndiotactic PMMA. Hatada et al. [24] reported a detailed study of the complex formation, using highly stereoregular PMMA polymers with narrow molecular weight distribution. The effect of tacticity on the characteristics of Langmuir-Blodgett films of PMMA and the stereocomplex between isotactic and syndiotactic PMMA in such monolayers at the air-water interface have been reported in a series of papers by Brinkhuis and Schouten [27,27a]. Similar to this system, Hatada et al. [28] reported stereocomplex formation in solution and in the bulk between isotactic polymers of / -(+)- and S-(—)-a-methylbenzyl methacrylates. [Pg.7]

The second large group of chapters spedfically describes the synthetic aspects of ROP/ROMP. In this section, the architecture of polymers prepared by ROMP, functionalization of poly (ethylene oxide), chain extension by ROP, nonlinear polyethers, as wdl as ROP in heterogeneous media are discussed. It also describes methods of polymerization that provide regular and mostly spherical partides, and gives for the first time a review of the kinetics and mechanism of this particular system that resembles emulsion vinyl polymerization. The chapter on polymerization in confined space (encompassing matrix polymerization) summarizes results that may open the way to the replica polymerization, a process that is typical for the matrix synthesis of biomacromolecules in nature. [Pg.1]

Tan defined template (or matrix or replica) polymerization as "any reaction implying propagation of polymer chains along template macromolecules during at least part of its lifetime". [Pg.833]

Strictly speaking, in replica polymerization, the template polymer and the polymer originating in the presence of that template must be identical. [Pg.833]

The term replica polymerization was first used by Szwarc" and variously termed matrix or replica polymerization later by Bamford. The polymer formed, sometimes called daughter polymer, is, in most cases, complexed with the template and can be separated by an additional process. [Pg.833]

The term replica polymerization shows some analogies between natural biological processes known as replication or transcription. [Pg.833]

Porous polymer materials, especially in particulate form, are of interest in a diverse range of applications, including controlled drug delivery, enzyme immobilization, molecular separation technology, and as hosts for chemical synthesis [101-104]. MS materials have been used as hosts for the template synthesis of nanoporous polymer replicas through in situ polymerization of monomers in the mesopores [105-108]. [Pg.221]

Place grids with labeled bacteria on the cathode plate in a bell jar of the plasma polymerization replica apparatus. [Pg.298]

Yamaguchi M, Kondo I. Immunoelectron microscopy of Proteus vulgaris by the plasma polymerization metal-extraction replica method differential staining of flagellar (H) and somatic (0) antigens by colloidal golds. J Electron Microsc 1989 38 382-388. [Pg.303]

Tanaka A, Sekiguchi Y, Kuroda S. A new replica method for electron microscopic studies of a plasma polymerization film with a glow discharge. Seikagaku 1983 55 1212-1219. (in Japanese)... [Pg.303]

FIGURE 2.23 Scheme for fabrication of plastic microdevices from silicon master using an intermediate soft mold, (a) Silicon structures are fabricated using conventional photolithography and reactive ion etching, (b) PDMS is cured in situ over the silicon master, (c) Polystyrene is hot embossed onto the PDMS mold or polymerized in situ from partially polymerized styrene, (d) Polystyrene replica is separated from the mold [85]. Reprinted with permission from Springer Science and Business Media. [Pg.36]

In addition to creating semiconductor or metal replicas of the channels of mesoporous materials, which are expected to display electron and hole quantum confinement effects, forming fibers of polymers could lead to materials with novel electrical, magnetic, optical or mechanical properties. To this end, oxidative polymerization of aniline within the channels of mesoporous silica has been reported [91]. Convincing spectroscopic evidence for intrachannel polymerization of aniline to poly(aniline) was provided. Extracted polymer had a molecular weight considerably smaller than that of the bulk material under similar conditions indicative of a diffusion constraint imposed upon the polymerization and growth of monomer inside the channel space of mesoporous silica. [Pg.64]

The morphology of the plasma polymerized films has been examined by electron microscopy by a number of workers ( 3,, 48). Figure 12 shows the replica electron micrograph of plasma polymerized ethylene deposited on chromium substrate at several gas pressures (46). The presence of powder particles is clearly evidenced in Figures 12a-c. The size and density of the powdery products decrease with increasing pressure until at a pressure of 3 torr when the polymer is mainly film and contains very few particles. [Pg.14]


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See also in sourсe #XX -- [ Pg.103 ]




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