Styrene bulk polymerization

Polymerization conditions styrene bulk polymerization, 70 °C, 1 h. h Catalyst activity without hydrogen as 100. 

In another example, the novel Rh(I) complex Rh-2 was employed with CC14 for MMA and styrene bulk polymerizations at 60 °C, which reached 90% conversion in 14 h.140 The MWD of PMMA was narrower than that of polystyrene MJMn = 1.43 vs 2.08), while the initiation efficiency was very low in both cases. 

Fig. 15. Transformation of a gel permeation chromatography (GPC) trace of a stationary styrene bulk polymerization at 25° C with carbon tetrachloride as transfer agent, into a semilogarithmic number distribution according to equation 173.

Lousberg HHA, Boelens HFM, Le Comte EP, Hoefsloot HCJ, Smilde AK. On-line determination of the conversion in a styrene bulk polymerization batch reactor using near-infrared spectroscopy. J Appl Polym Sci 2002 84 90-98. 

Online NIR spectroscopy has been used to measure conversion versus time traces for cumyl dithiobenzoate (CDB)-mediated styrene bulk polymerizations up to 2.5 kbar. MMDs of the resulting polymer were determined by SEC. ° ... 

Figure 22 Pressure dependence of the rate of polymerization at 70 X for CDB-mediated styrene bulk polymerization at three CDB levels initiator azobisisobutyronitrile concentration 1 x lO" mol The dashed line represents conventional polymerization, that is, without CDB, under otherwise identical conditions. From Arita, T. Buback, M. Janssen, 0. Vana, P. Macromol. Rapid Commun. 2004, 25,1376. ° ...

Figure 4 Tower reactors for styrene bulk polymerization.

Suspension polymerization produces beads of plastic for styrene, methyl methacrviaie. viny l chloride, and vinyl acetate production. The monomer, in which the catalyst must be soluble, is maintained in droplet fonn suspended in water by agitation in the presence of a stabilizer such as gelatin each droplet of monomer undergoes bulk polymerization. In emulsion polymerization, ihe monomer is dispersed in water by means of a surfactant to form tiny particles held in suspension I micellcsK The monomer enters the hydrocarbon part of the micelles for polymerization by a... 

Anionic polymerization of lactams was shown to proceed according to what is called the activated monomer mechanism. With bischloroformates of hydroxy-terminated poly(tetramethyleneglycol) and poly(styrene glycol) as precursors for a polymeric initiator containing N-acyl lactam ends, block copolymers with n-pyrrol-idone and e-caprolactam were obtained by bulk polymerizations in vacuum at 30 and 80 °C, respectively361. ... 

Classification of Processes and Reactors. Most styrene polymers are produced by batch suspension or continuous mass processes. Some are produced by batch mass processes. Mass in this sense includes bulk polymerization of the polymer... 

One of the few attempts to examine a polymerization reactor in periodic operation experimentally is the work of Spitz, Laurence and Chappelear (X6)who reported the influence of periodicity in the initiator feed to the bulk polymerization of styrene in a CSTR. To induce periodicity the initiator feed was pulsed on-and-off and the reactor output compared with steady-state operation with the same time-averaged initiator input. 

There is an interior optimum. For this particular numerical example, it occurs when 40% of the reactor volume is in the initial CSTR and 60% is in the downstream PFR. The model reaction is chemically unrealistic but illustrates behavior that can arise with real reactions. An excellent process for the bulk polymerization of styrene consists of a CSTR followed by a tubular post-reactor. The model reaction also demonstrates a phenomenon known as washout which is important in continuous cell culture. If kt is too small, a steady-state reaction cannot be sustained even with initial spiking of component B. A continuous fermentation process will have a maximum flow rate beyond which the initial inoculum of cells will be washed out of the system. At lower flow rates, the cells reproduce fast enough to achieve and hold a steady state. 

FIGURE 13.7 Performance of a laminar flow, tubular reactor for the bulk polymerization of styrene Tin = 35°C and F = 1 h. (a) Stability regions, (b) Monomer-conversion within the stable region. 

We can readily polymerize styrene by a variety of methods including solution, emulsion, suspension, and bulk processes. Historically, bulk polymerization was the first commercial process, but it has now largely been superseded by solution and suspension polymerization. 

The data in Table I are not directly comparable, since the viscosity of the 3-isomer was determined in benzene while the others were measured in DMSO. In addition, the first two polymers were prepared in bulk polymerizations, while the polymerization of methyl 3-vinylsalicylate was carried out with the monomer diluted 1 1 with benzene. Thus no certain conclusion can be drawn the data are, however, an indication of possible difficulty in radical polymerization of substituted styrenes bearing a phenol ortho to the vinyl group. 

Ever since 1962, when Williams, Okamura, and their associates started to publish propagation rate-constants k+p for the cationic bulk polymerization of cyclo-pentadiene, isobutene, styrene, a-methylstyrene and isopropylvinyl ether by ionizing radiations, these constants have been accepted as the best, most likely, values for the k+p of unpaired cations in a medium of low-polarity, and those obtained subsequently by Stannett and his collaborators, using similar methods, enjoyed the same status, (The loci classici are Bates et al. (1962), Bonin et al. (1964), Taylor Williams (1969) and the three papers by Ueno et al. (1967), Hayashi et al. (1967) and Williams et al. (1967).)... 

The bulk polymerization process needs monomers that can dissolve their own polymers. (There s no solvent or water in the reactor to keep the polymer floating around.) Styrene and some of the more commonly used comonomers have this property, and so its generally cheaper to use bulk polymerization. 

Additionally, TADDOL derivative (9) which contained an additional styrene group was first prepared in solution and then underwent bulk polymerization in the presence of various porogenic agents in order to obtain soHd-phase-bound catalyst (10) with the desired porosity (Scheme 4.5) [67]. 

Would it be safe to polymerize styrene by bulk polymerization in a 55 gal drum ... 

What would happen if one added a small amount of an inhibitor to styrene before bulk polymerization ... 

Fig. 3-21 Plots of ln([M]o/[M]) versus time for ATRP polymerizations of styrene at 110°C with CuBr, 1-phenylethyl bromide (I), and 4,4-di-5-nonyl-2,2 -bipyridine (L). Bulk polymerization ( ) [M] = 8.7 M, [CuBr]0 = [L]0/2 = [I] = 0.087 M Solution polymerization in diphenyl ether (o) [M] = 4.3 M, [CuBr]0 = [L]0/2 = [I] = 0.045 M. After Matyjaszewski et al. [1997] (by permission of American Chemical Society, Washington, DC) an original plot, from which this figure was drawn, was kindly supplied by Dr. K. Matyjaszewski.

Consider the bulk polymerization of neat styrene by ultraviolet irradiation. The initial polymerization rate and degree of polymerization are 1.0 x 10 3 mol L 1 s 1 and 200, respectively, at 27°C. What will be the corresponding values for polymerization at 77°C ... 

Some effect of viscosity on r has been observed [Kelen and Tudos, 1974 Rao et al., 1976]. Copolymerization of styrene (Mil-methyl methacrylate (M2) in bulk leads to a copolymer containing less styrene than when reaction is carried out in benzene solution [Johnson et al., 1978]. The gel effect in bulk polymerization decreases the mobility of styrene resulting in a decrease in r and an increase in r%. 

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

The bulk polymerization of styrene to give a narrow molecular weight distribution has appeared in a U.S. patent [45]. The polydispersity reported was... 

Several references to the bulk polymerization of styrene are worth consulting [46-50], Most consider a continuous bulk polymerization apparatus with some using spraying of the monomer through a nozzle. The controlled evaporation of unreacted monomer is one method of removing the heat of reaction. 

The history of styrenic polymers is documented by Amos (1) and Scheirs (2). The first patent of the suspension or bulk polymerization, respectively, of styrene in presence of rubbers goes back to the 1950s (3,4). 

The simplest procedure for grafting copolymerization, in terms of number of components in the reaction medium, is a bulk polymerization of the monomer in mixture with the molten polyamide. This has been claimed in an earlier patent (2), related to improvements in dyeability and hydrophylic properties of the resulting yam, obtained by melt spinning of the product of reaction with monomers such as 2,5-dichloro styrene, lauryl methacrylate, N-vinyl pyrrolidone, and N-vinyl carbazole. 

Bulk polymerization was also studied briefly (Table II), adapting a technique useful in production of impact styrene (I). Solid polybuta-diene was dissolved in styrene, mixed with acrylonitrile and/or methyl methacrylate, charged into a 12-ounce crown-cap bottle, flushed with nitrogen, and tumbled end-over-end at 42 rpm in a constant-temperature water bath for 16 hours at room temperature, 48 hours at 80 °C, and 48 hours at 90°C, then heated in an oven 24 hours at 110°C and 24 hours at 150°C. ABS polymerization produced a grainy, inhomogeneous, light-... 

---