Radical and anionic polymerizations

The polymeric coat formed on the substrate by radical and anion polymerization has been observed to be mosaic [313-315]. The polymer was there in the form of... 

Co-polymerizations and homo-polymerizations of monomers such as dienes or 4-methylene dioxolan, in which two or more types of ion may propagate simultaneously, are further examples of enieidic polymerizations. These dienes, of course, also provide examples of eniedic radical and anionic polymerizations. Indeed the idea of dieidic polymerization has been suggested by several authors in relation to anionic polymerizations it arose from the aggregation in solution of the lithium alkyls [135], and similar phenomena. 

What reaction conditions determine the relative amounts of 1,2-, cis 1,4-, and trans 1,4-polymerization in the radical and anionic polymerizations of 1,3-butadiene Indicate... 

To broaden our overall knowledge of process kinetics the first chapter of this volume deals with elementary reactions in radical and anionic polymerization it was written by G. V. Schulz, the first recipient of the H. Staudinger Award. It is followed by a discussion on monomer constitution and stereocontrol in radical polymerization by H. G. Elias et al. 

Since polystyrene is one of the oldest commercial polymers with over 9 million tonnes/yr of sales, there have been thousands of patents issued covering all aspects of its manufacture and property enhancement. The styrene monomer readily polymerizes to polystyrene either thermally or with free-radical initiators (see Chapter 6 on free-radical polymerization and Chapter 8 on nitroxide-mediated polymerization). Commercial processes for the manufacture of polystyrene are described in Chapter 3 while process modelling and optimization of styrene polymerization is examined in Chapter 5. Styrene also can be polymerized via anionic and Ziegler-Natta chemistries using organometallic initiators. Using free radical and anionic polymerization chemistries, the... 

Examples include control of molecular weight in step-growth polymerization, number-average degree of polymerization in step-growth polymerization of nonstoichio-metric monomer mixtures, free-radical and anionic polymerizations of styrene, and ethene oligomerization to linear 1-olefins in the Shell Higher Olefins Process. 

We have synthesized the first poly(acylsilane) by a free-radical polymerization of l-trimethylsilyl-2-propen-l-one. However, our attempts at the free-radical and anionic polymerization of poly(l-trimethylsilyl-2-methyl-2-propen-l-one) failed. 

Mechanism and kinetics of cationic poiymerization initiation. Unlike free-radical and anionic polymerization, initiation in cationic polymerization employs a true catalyst that is restored at the end of the polymerization and does not become incorporated into the terminated polymer chain. Initiation of cationic polymerization is brought about by addition of an electrophile to a monomer molecule. TVpical compounds used for cationic polymerization include protonic acids (e.g., H2SO4, H3PO4), Lewis acids (e.g., AICI3, BF3, TiCl4, SnCl4), and stable carbenium-ion salts (e.g., triphenylmethyl halides, tropylium halides) ... 

Free-radical and anionic polymerizations of TAD-DOL—MA (30) proceed exclusively via a cyclization mechanism, and the obtained polymer seems to have a helical conformation with an excess helicity.92-94 The main chain structure of poly(TADDOL—MA) with cyclized units (poly-30) is different from that of all other polymethacrylates discussed here. Similar monomers have been synthesized and polymerized.95... 

Both free-radical and anionic polymerization produce PBs that have mixed microstructures. Neither of these routes produces a rubber that can replace the high tack, green strength, or gum tensile of natural rubber. However, these PBs have been useful in many applications. 

A brief review of the radical and anionic polymerization of allyl acrylate and allyl acrylamides has appeared in Spanish [85]. 

Besides the radical and anionic polymerization at the interface, polyaddition reactions can also be carried out at the droplet s interface. This technique can be realized in direct and inverse miniemulsion which enables the encapsulation of either hydrophobic or hydrophilic liquids. It is important to mention that the encapsulated liquids have to be a non-solvent for the generated polymer shell if capsules are the desired morphology. 

Styrene-butadiene rubber (SBR) for automobile tires is a random copolymer. It is prepared by two methods, free-radical and anionic polymerization, both of which are carried out on a mixture of styrene and 1,3-butadiene. Free-radical initiation is essentially nonselective and gives the random copolymer. Anionic initiation is carried out under conditions designed to equalize the reactivity of the two monomers so as to ensure randomness. 

Very strangely, N,N-diaUcylmethacrylamides such as N,N-dimethyl- and N,N-butylmethacrylamide were not polymerized at all under radical and anionic polymerization conditions [121]. On the basis of H and NMR studies, and Modified... 

Other examples include the free radical polymerization of vinyl isocyanate with subsequent anionic polymerization of the isocyanate side groups, as well as the corresponding polymerization of acrylonitrile or poly(acrylonitrile). Free radical and anionic polymerizations are to be preferred over those initiated by cations, since cationic polymerization frequently tends to give rise to transfer reactions which interrupt the transannulation. For example, in the cyclization of natural rubber with the aid of concentrated acids or Lewis acids, an average of only three transannular rings is obtained [see Equation (25-9)]. The intermolecular elimination of water from poly(vinyl methyl ketone) only produces single, double, and triple rings ... 

PVPA can also be obtained by hydrolysis of poly(dimethyl vinylphosphonate) (PDMVP), which was synthesized both through free radical and anionic polymerization. Structural analysis revealed that PDMVP obtained by anionic polymerization is isotactic-rich. 

Polystyrene-rofaxa-bisparaphenylene- 34-crown-10 Polystyrene-rofaxa-30-crown-10 With a triphenyl blocking group free-radical and anionic polymerizations. Two TgS observed. [239]... 

Depolymerization is carried out under vacuum in the presence of an acid such as sulphur dioxide. The monomer which distils from the reaction mixture is collected in a vessel containing radical and anionic polymerization inhibitors. 

PS- f-PI, (PS-g-PI)-6-PS, and (PS-g-PS)-6-(PS-g-PI) copol5uners have been synthesized by using a combination of TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxy) living free-radical and anionic polymerization (27) (Fig. 5). 

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