Polymerization of Styrene with

Anionic Polymerization. Addition polymerization may also be initiated and propagated by anions (23—26), eg, in the polymerization of styrene with -butyUithium. The LL gegen ion, held electrostatically in... 

Over the range in which the rate of polymerization is proportional to the square root of the initiator concentration, Rj, may be replaced in Eq. (36) with the coefficients of the terms being appropriately altered. The contributions of the various sources of chain ends in the polymerization of styrene with benzoyl peroxide at 60°C are shown in Fig. 15 as functions of the initiator concentration.The uppermost curve represents the total number of polymer molecules per unit, and the differences between successive curves represent the contributions of the separate processes indicated. 

The transfer constant Cj may be isolated from Eq. (39) by utilizing the rate of polymerization and Eq. (12). According to the result of Mayo, Gregg, and Matheson on the polymerization of styrene with benzoyl peroxide at 60°C (see Fig. 8)... 

M. St. C. Flett and P. H. Plesch, J, Chem. Soc., 1952 3355, found evidence for the presence of the trisubstituted ethylene end group and also for trichloro-acetate end groups in low molecular weight polyisobutylenes prepared at 0°C using TiCh and CI3COOH as catalyst and co-catalyst, respectively. For results on the similar polymerization of styrene with TiCh, see P. H. Plesch, J. Chem. Soc., 1963, 1653, 1659, 1662. 

Living Radical Polymerization of Styrene with TEMPO... 

Taniguchi T, Takeuchi N, Kobaru S, Nakahira T (2008) Preparation of highly monodisperse fluorescent polymer particles by miniemulsion polymerization of styrene with a polymerizable surfactant. J Colloid Interface Sci 327 58-62... 

Wang GM, van Beylen M (2003) Influence of 7t-complexing agents on the anionic polymerization of styrene with lithium as counterion in cyclohexane. 1. Effect of durene. Polymer 44 6205-6210... 

Fig. 4-3 Plot of percent conversion versus time for emulsion polymerizations of styrene with different concentrations of potassium laurate at 60° C. The moles of emulsifier per polymerization charge (containing 180 g H2O, 100 g styrene, 0.5 g K2S2O8) are 0.0035 (plot 1), 0.007 (plot 2), and 0.014 (plot 3). After Williams and Bobalek [1966] (by permission of Wiley-Interscience, New York).

Polymerization of Styrene with Potassium Peroxodisulfate in Emulsion... 

Bulk Polymerization of Styrene with 2,2 -Azobisisobutyronitrile in a Dilatometer... 

Stereospedfic Polymerization of Styrene with Ziegler-Natta-Catalysts... 

As was stated above, the interpretation that the field affects the dis-sodation state of the growing chain ends was not uniquely substantiated by the experimental data, except those on copolymerizations. Thus it is interesting to investigate the field influence on much simpler systems than cationic homopolymerizations. For this purpose we have chosen living anionic systems in which only propagation steps are involved. The system first studied was a living anionic polymerization of styrene with n-butyllithium in the binary mixtures of benzene and tetrahydrofuran (17,24) and in the binary mixtures of benzene and dimethoxyethane (15). 

The polymerization of styrene with less anionic butyllithium has been studied by several workers (31, 32, 33). The results of Tobolsky and Boudreau (34) showed that the butyllithium polymerization of styrene follows the electronic behavior of an anionic reaction. Electron releasing groups on the aromatic ring decreased the reactivity of the monomer. Braun and co-workers and Worsfold and Bywater (35) have studied the production of isotactic polystyrene by butyllithium catalysis. Worsfold and Bywater found that water plays an important role in the isotactic polymerization and concluded that the production of lithium hydroxide in situ is important for the isotactic steric control. Added lithium butoxide, lithium methoxide or lithium carbonate were not effective. They concluded the associated forms of butyllithium do not produce isotactic steric control but require association with lithium hydroxide. 

Tsou, Magee and Malatesta (39) showed the effect of catalyst ratios on steric control m the polymerization of styrene with alkyllithium and titanium tetrachloride. These authors have shown that the isotactic polymer was produced when the butyllithium to titanium ratio was kept within the limits of 3.0 to 1.75. Outside of this critical range, amorphous polymers were produced. In the discussion of this paper, Friedlander (40) pointed out the cationic nature of the low-lithium-to-titanium-ratio-catalysts which also produced considerable rearrangement of the phenyl groups. Above 2.70 lithium to titanium ratio, an anionic type polymerization set in, which produced atactic polymer. At low ratios cationic catalysis also produced atactic polymer. Tsou and co-workers concluded that crystallinity of the catalyst is not important for steric order in the polymer. 

Subsequent polymerization of styrene with these MMA prepolymers as initiators leads to block copolymers of an ABA-type due to the tendency of the growing polystyrene chains to terminate by combination ... 

Let us determine the value of e by comparing the transient kinetic behavior of monomer conversion in continuous emulsion polymerization of styrene with the model prediction by the Nomura and Harada model. It is reported in the literature that sustained... 

Block copolymers, polyclhylcnc-fr/oc/c-polystyrene (PE-fc-PS) and PP-fo-PS, were prepared by the polymerization of styrene with terminally lithiated PO macroinitiators [31]. 

Fig. 5 Synthesis of cyclic polymer using polymerization of styrene with cyclic initiator...

Polymer stereoregularity obtained with styrene and butadiene is particularly significant. In the polymerization of styrene with the three cocatalyst-dependent systems... 

The emulsion polymerization of styrene with shellac salt stabilizer yields a highly crosslinked, F/T stable emulsion from which it is not possible to extract all the shellac by conventional means (21). This may be interpreted in a similar manner although it has not, as yet, been possible to determine the sites on the shellac which undergo chain transfer. 

Bywater and Worsfold [145] have measured the initiation rate in the polymerization of styrene with w-BuLi and sec.-BuLi in benzene. The active centres... 

Cationic polymerizations of styrene, 2-methylpropene, vinylnaphthalene, indene, etc. at temperatures about 273 K yield only low polymers. Polymerization of styrene with HC104 in chlorinated solvents at room tern-... 

Deb and Gaba [14] studied the polymerization of styrene with diben-zoylperoxide and 2,2 -azobisisobutyronitrile. When deriving the kinetic relations, they considered mutual combination of primary radicals (and of their... 

The dissociation constants of trityl and benzhydryl salts are KD 10 4 mol/L in CH2C12 at 20° C, which corresponds to 50% dissociation at 2-10-4 mol/L total concentration of carbocationic species (cf. Table 7) [34]. The dissociation constants are several orders of magnitude higher than those in analogous anionic systems, which are typically KD 10-7 mol/L [12]. As discussed in Section IV.C.l, this may be ascribed to the large size of counterions in cationic systems (e.g., ionic radius of SbCL- = 3.0 A) compared with those in anionic systems (e.g., ionic radius of Li+ 0.68 A), and to the stronger solvation of cations versus anions. However, the dissociation constants estimated by the common ion effect in cationic polymerizations of styrene with perchlorate and triflate anions are similar to those in anionic systems (Kd 10-7 mol/L) [16,17]. This may be because styryl cations are secondary rather than tertiary ions. For example, the dissociation constants of secondary ammonium ions are 100 times smaller than those of quaternary ammonium ions [39]. 

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