Styrene emulsion copolymerization

Commercial SBR is produced by either emulsion or solution copolymerization of butadiene and styrene. Emulsion copolymerization is either a cold (41°F) or hot (122°F) process. The copolymers from the hot and cold processes have principal differences in molecular weight, molecular weight distribution, and microstructure, as shown in Table 5.1. The solution copolymerization process for the production of... 

Chatzi EG, Kammona O, Kiparissides C. Use of a midrange infrared optical-fiber probe for the on-line monitoring of 2-ethylhexyl acrylate/styrene emulsion copolymerization. J Appl Polym Sci 1997 63 799-809. 

The soapless seeded emulsion copolymerization method was used for producing uniform microspheres prepared by the copolymerization of styrene with polar, functional monomers [115-117]. In this series, polysty-rene-polymethacrylic acid (PS/PMAAc), poly sty rene-polymethylmethacrylate-polymethacrylic acid (PS/ PMMA/PMAAc), polystyrene-polyhydroxyethylmeth-acrylate (PS/PHEMA), and polystyrene-polyacrylic acid (PS/PAAc) uniform copolymer microspheres were synthesized by applying a multistage soapless emulsion polymerization process. The composition and the average size of the uniform copolymer latices prepared by multistage soapless emulsion copolymerization are given in Table 11. 

Poly(azophenylene-o-carborane) (see 6) has been prepared from diphenyl-o-carborane by means of nitration, reduction, and acylation to initially give 1,2-bis(/ -nitroso-acetylaminophenyl)-o-carborane (NAFC). Rapid decomposition in solution affords phenylene amino phenyl carborane (PAFC) by recombination of phenylene and azophenylene radicals.40 These radicals have also been utilized to form copolymers of carborane-containing copolymers from monomers polymerizable via radical mechanisms. Thus, copolymers of polystyrene and poly(azophenylene) can be readily formed by means of emulsion copolymerization of styrene with NAFC decomposition products. 

By emulsion copolymerization (ECP) of self-emulsifying unsaturated polyesters (EUP) and bifunctional monomers, such as styrene (S), microgels may be prepared which have a rather uniform diameter [109]. This uniformity of size is due to a special mechanism of particle formation involved in using EUP as comonomers. 

The use of a single-stage CSTR for HF alkylation of hydrocarbons in a special forced-circulation shell-and-tube arrangement (for heat transfer) is illustrated by Perry et al. (1984, p. 21-6). The emulsion copolymerization of styrene and butadiene to form the synthetic rubber SBR is carried out in a multistage CSTR. 

I, too, was caught up in the wave of enthusiasm for this new science which had the lofty goal of relating the properties of materials to their molecular structure, and, in the end, to "tailor-making molecules for specific properties. Since one of the big developments at that time was the newly-started synthetic rubber programs of the American and Canadian governments, I chose the topic of the emulsion copolymerization of butadiene-styrene as the subject of my doctoral dissertation. 

Fig. 11.1.7 Conversions of styrene and acrylamide in soap-free emulsion copolymerization.

In Figure 2, dN/dW is plotted as a function of W for two series of commercial samples withdrawn from an experimental continuous reactor line in which butadiene and styrene were copolymerized in emulsion using a 1500-type recipe at 5°C. The conversion marking the onset of predominant crosslinking is given by the point at which the curves cut the W axis—that is, at 53 and 57% conversions. 

Figure I. Rate of change in macromolecular population dN/ dw as a function of conversion in emulsion copolymerization of styrene and butadiene (styrene butadiene = 29 71 by tot) concentration of tert-dodecyl mercaptan (TDM) modifier in phm A — run 4, 0.10 O — run 6, 0.20 X — run 7, 0.23...

A selection of the results obtained 29) for the emulsion copolymerization of 1 with styrene at 10 °C using sodium lauryl sulphate as emulsifying agent and Rongalit / H202/Fe2+ as initiator are given in Table 3.4. 

Table 3.6. Results from the emulsion copolymerization of 2 with styrene at 5 °C J0 3n...

Commercial ABS is prepared primarily by free-radical emulsion copolymerization of styrene and acrylonitrile in the presence of polybutadiene latex (3). This method was therefore adapted for the preparation of ABS and MBS terpolymers and an intermediate AMBS tetrapolymer under similar conditions (Table I). Polymerizations were charged into 12-ounce crown-cap bottles, sparged and flushed with nitrogen, and... 

Thus in the emulsifier-free emulsion copolymerization the emulsifier (graft copolymer, etc.) is formed by copolymerization of hydrophobic with hydrophilic monomers in the aqueous phase. The ffee-emulsifier emulsion polymerization and copolymerization of hydrophilic (amphiphilic) macromonomer and hydro-phobic comonomer (such as styrene) proceeds by the homogeneous nucleation mechanism (see Scheme 1). Here the primary particles are formed by precipitation of oligomer radicals above a certain critical chain length. Such primary particles are colloidally unstable, undergoing coagulation with other primary polymer particles or, later, with premature polymer particles and polymerize very slowly. 

The emulsifier-free emulsion copolymerization of styrene and poly(meth-acrylic acid) (PMA) macromonomers... 

The colloidal stability of polymer dispersion prepared by the emulsion copolymerization of R-(EO)n-MA was observed to increase with increasing EO number in the macromonomer [42, 96]. Thus C12-(EO)9-MA did not produce stable polymer latexes, i.e., the coagulum was observed during polymerization. This monomer, however, was efficient in the emulsion copolymerization with BzMA (see below). The C12-(EO)20-MA, however, appears to have the most suitable hydrophilic-hydrophobic balance to make stable emulsions. The relative reactivity of macromonomer slightly decreases with increasing EO number in macromonomer. The most hydrophilic macromonomer with co-methyl terminal, Cr(EO)39-MA, could not disperse the monomer so that the styrene droplets coexisted during polymerization. The maximum rate of polymerization was observed at low conversions and decreased with increasing conversion. The decrease in the rate may be attributed to the decrease of monomer content in the particles (Table 2). In the Cr(EO)39-MA/St system the macromonomer is soluble in water and styrene is located in the monomer droplets. Under such conditions the polymerization in St monomer droplets may contribute to the increase in r2 values. 

A series of amphiphilic diblock macromonomers were successfully used as steric stabilizers in the emulsion polymerization styrene [98]. Copolymerization led to the formation of polymer latexes of high colloidal stability. These... 

Emulsifier-Free Emulsion Copolymerization of Styrene with Acrylamide and Its Derivatives... 

We will describe its use for controlling the styrene-acrylonitrile emulsion copolymerization system. Results concerning copolymer compositions, molecular characteristics and particle sizes will be compared to the corresponding ones from batch or semi-continuous processes. 

Previous kinetic study of emulsion copolymerization of styrene (S) and acrylonitrile (AN) leads us to determine (4) the reactivity ratios as ... 

The first work on the emulsion copolymerization with a macromonomer has been reported by Ito et al. [132] for styrene using PEO macromonomer 49. Subsequently, several research groups have reported the synthesis and some properties of latex particles containing PEO chains from 26,27,36,50-52, attached to their particles surface [132-140]. Ottewill and Satgurunathan [134] and West-by [ 135] reported the preparation of such particles in a multistage emulsion po-... 

Kobayashi et al. [143-146] have synthesized several types of amphiphilic po-ly(2-oxazoline), 34 and its block cooligomers, 53-55, and applied them to soap-free emulsion copolymerization of styrene and vinyl acetate to produce mono-disperse, submicron-sized latex particles. They found that the particle size significantly depended on the type of macromonomer used and generally decreased with increasing the macromonomer concentration. 

The latex particle diameter produced in the emulsion copolymerization of styrene with partially neutralized poly(methacrylic acid) macromonomers, 48, was studied as a function of degree of neutralization [127]. The latex particle... 

Schoonbrood, H.A.S., Unzue, MJ., Beck, O. and Asua, J.M. (1997) Reactive surfactants in heterophase polymerization. 7. Emulsion copolymerization mechanism involving three anionic polymerizable surfactants (surfmers) with styrene-butyl acrylate acrylic acid. Macromolecules, 30, 6024-33. 

Sindt, O., Gauthier, C., Hamaide, T. and Guyot, AJ. (2000) Reactive surfactants in heterophase polymerization. XVI. Emulsion copolymerization of styrene-butyl acrylate-acrylic acid in the presence of simple maleate reactive surfactants. /. Appl. Polym. Sci, 77,2768-76. 

Soula, O. and Guyot, A. (1999) Styrenic surfmer in emulsion copolymerization of acrylic monomers. I. Synthesis and characterization of polymerizable surfactants. Langmuir, 15,7956-62. 

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