Dodecyl methacrylate, polymerization

Smith et al.511 have recently suggested a composite model based on similar considerations to predict k over the entire chain length range. Experimental data for k A for dodecyl methacrylate polymerization consistent with such a model have been provided by Buback et rd. J... 

In addition to MMA, a variety of methacrylic esters were polymerized rapidly to the corresponding polymers with narrow MWDs in the presence of methylaluminum bis(2-ferf-butyl-4-methoxyphenolate) (3c). The successful examples include ethyl methacrylate (EMA), isopropyl methacrylate ( °PMA), n-butyl methacrylate ("BMA), isobutyl methacrylate ( °BMA), benzyl methacrylate (BnMA), and dodecyl methacrylate (Cj2MA), where the Mn values were all close to the predicted values (Mn j ) with the Mw/Mn ratios below 1.1 (Table 3, runs 1-4,6,7). The polymerization of ferf-butyl methacrylate ( BMA) is the only exception, where the monomer conversion hardly increased even after 24 h. 

It is well known that emulsion polymerizations of highly water-insoluble monomers such as octadecyl methacrylate (OM), dodecyl methacrylate (DM), and stearyl acrylate (SA) are generally not feasible using traditional surfactant... 

Dispersion polymerization has also been applied to the ring opening polymerization of e-caprolactone and lactide in heptane-dioxane (4/1 v/v) with poly(dodecyl methacrylate)-g-poly(e-caprolactone) as stabilizer [97]. Diethyl-aluminium ethoxide and tin(II) 2-ethylhexanoate were used as initiators in these two systems, respectively, to obtain functional microspheres with a narrow particle size distribution and a narrow molecular weight distribution [98]. Table 2 provides an overview of microspheres obtained by living dispersion polymerization. 

Dodecyl methacrylate (DMA) and stearyl methacrylate (SMA) are efficiently reactive coemulsifiers in the St mini-emulsion polymerization using SDS as the emulsifier [ 13]. The high coemulsifier (hydrophobe) activity of these unsaturated compounds results from the fact that the Rp data are almost the same in the mini-emulsion polymerizations stabilized by SDS/CA, SDS/DM A, SDS/SMA and SDS/HD. The average particle size (D) of the reaction mixture comprising both the monomer droplets and latex particles in the SDS/CA or SDS/DMA stabilized polymerization decreases rapidly from ca. 300-350 nm to a minimum (ca. 115— 125 nm), followed by a gradual increase to a plateau (ca. 125-150 nm). The initial abrupt decrease in D is attributed to the generation of particle nuclei by ho-... 

Ueda et al. conducted a systematic study involving the copolymerization of MPC with other vinyl compounds by conventional radical polymerization. Typically, when the MPC was copolymerized in solution with styrene (St) and various alltyl methacrylates such as n-butyl methacrylate (BMA, forming PMB), f-butyl methacrylate (t-BMA), n-hetyl methacrylate (HMA, forming PMH), n-dodecyl methacrylate (DMA, forming PMD), or n-stearyl methacrylate (SMA, forming PMS), the polymerization progressed very well, and a statistically random sequence was obtained. The radical copolymerization of MPC (Ml) and St (M2) in ethanol resulted in the following copolymerization parameters monomer reactivity ratio for Mi and M2 are ri = 0.39, V2 = 0.46, respectively. Also, the Qi and values of the MPC are calculated as Qi = 0.76 and e-i = + 0.51, respectively. In addition, for an MPC (Mi) and MMA (M2) system, the monomer reactive ratio values are ri = 1.61, r2 = 0.66. 

Fig. 12. Temperature dependence of the effective propagation rate coefficient k f observed in the bulk polymerization of dodecyl methacrylate. The data are taken from Ref 429.

Buback M, Muller E, Russell GT. SP-PLP-EPR smdy of chain-length-dependent termination in free-radical polymerization of n-dodecyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate evidence of composite behavior. J Phys Chem A 2006 110 3222-3230. 

Until recently, there was only one report about the use of reactive costabilizers in miniemulsion polymerization [125]. In that study, dodecyl methacrylate (DMA) and stearyl methacrylate (SMA) were been used as cosurfactants with SDS and compared with cetyl alcohol (CA) and hexadecane (HD). It has been shown that DMA behaves like CA, whereas SMA displays a behavior similar to HD in terms of droplet size stability as well as in the particle size distribution of latexes. However, the distribution obtained using these reactive hydrophobes is in both cases somewhat narrower than for the model compounds. More recently, the same team published a study where in the polymerization of styrene in miniemulsions stabilized using DMA or SMA, small quantities of acrylic acid or methacrylic acid were added [126]. The authors were chiefly interested in the nucleation mechanism. Surprisingly, the addition of these hydrophilic monomers tends to favor nucleation within the droplets more than homogeneous nucleation, which is the dominating mechanism in the absence of these water-soluble monomers. The explanation lies in the fact that the styrene-carboxylic co-oligomers, because they are much more hydrophilic, are more reluctant to nucleate new particles. 

Poly (dodecyl acrylate)-gra/t-poly(D,L-lactide) could also be obtained in situ in dispersion polymerization of D,L-lartide initiated with stannous 2-ethylhexanoate and carried out in the presence of poly [(dodecyl methacrylate)-co-(2-hydro-xyethyl methacrylate)] (see Scheme 4). ... 

Figure 7 Dependence of the diameters of poly(D,L-lactide) microspheres synthesized by ring-opening polymerization on the concentration of the poly(dodecyl methacrylate)-gfra/f-poly(D,L-lactide) stabilizers stabilizer Gi (circle), G2 (triangle), and G3 (squares). The stabilizers are described in Tablet...

Plotted in Figure 13 is the pressure dependence of kp for polymerization of styrene, methyl acrylate (MA), and dodecyl acrylate (DA) as well as for several methacrylic acid esters at 30 °C. The kp value of linear alkyl esters increases in passing from methyl methacrylate (MMA) to dodecyl methacrylate (DMA). The reason behind this trend is seen in the reduced internal friction of the transition state stmcture with DMA, where the dipolar interactions of the carbonyl moieties are better shielded than in case of MMA. ... 

H) Homopolymerization and copolymerization Miniemulsion homopolymerizations of vinyl chloride, VAc, MMA, BA, styrene, VeovalO, dodecyl methacrylate, and stearyl methacrylate have been reported. °° ° In miniemulsion homopolymerization, once the polymer particles are formed, the process evolves in a similar manner as in interval III of a conventional emulsion polymerization, that is, in absence of monomer droplet phase. The differences in the polymerization rates observed when comparing conventional emulsion and miniemulsion polymerizations can be attributed to the different number of polymer particles formed in each process, which can be substantially different depending on the initiator systems employed. 

Up to now, poly(methyl methacrylate) and methyl methacrylate copolymers e.g. with styrene, butyl acrylate and dodecyl methacrylate) have been the most widely used acrylic polymers for nanocomposite preparation by emulsion and suspension polymerization. Less research has been based on other acrylic polymers, such as polyacrylonitrile, poly(butyl acrylate), " poly(butyl methacrylate), poly(2-ethylhexyl acrylate), poly(2-hydroxyethyl methacrylate), polyacrylamide, poly(lauryl acrylate)," poly(butyl acrylate-co-styrene)," " poly(acrylonitrile-co-styrene), poly(acrylonitrile-co-meth-acrylate)," poly(ethyl acrylate-co-2-ethylhexyl acrylate)" and poly(2-ethylhexyl acrylate-co-acrylic acid)," and sometimes small amounts of hydophilic acrylic monomers, such as hydroxyethyl methacrylate, methacrylic acid and acrylic acid, have been used as comonomers. " Therefore, it may be stated that, so far, the preparation of acrylic-clay nanocomposites has been based mainly on high glass transition temperature polymers, although nanocomposite materials with lower glass transition temperatures with improved or novel properties, which exhibit a balance of previous antagonistic properties, can also be achieved and are very desirable. Regarding nanocomposites of low glass transition temperature polymers, such as poly(butyl acrylate), poly(ethyl acrylate) and poly(2-ethylhexyl acrylate), which have been utilized as the main components of acrylic pressure-sensitive adhesives, little information is available. 

Mouron, D., Reimers, J., and Schork, F.J., Miniemulsion polymerization of methyl methacrylate with dodecyl mercaptan as cosurfactant. J. Polym. Sci. (Polym. Chem.), 34, 1073-1081 (1996). 

Materials. Methyl methacrylate (MMA) and methacrylic acid (MAA) monomers (Rohm and Haas), and n-dodecyl mercapten (Eastman Kodak Co.) were purified by vacuum distillation under nitrogen atmosphere to remove the inhibitor. Distilled-deionized and deoxygenated water was used in all polymerizations. Sodium lauryl sulfate (99% Onyx Maprofix 563) and Triton X-100 nonionic surfactant (Rohm and Haas), and potassium persulfate initiator (Fisher Scientific Co.) were used as received without further purification. 

Mouran et al. [105] polymerized miniemulsions of methyl methacrylate with sodium lauryl sulfate as the surfactant and dodecyl mercaptan (DDM) as the costabilizer. The emulsions were of a droplet size range common to miniemulsions and exhibited long-term stability (of greater than three months). Results indicate that DDM retards Ostwald ripening and allows the production of stable miniemulsions. When these emulsions were initiated, particle formation occurred predominantly via monomer droplet nucleation. The rate of polymerization, monomer droplet size, polymer particle size, molecular weight of the polymer, and the effect of initiator concentration on the number of particles all varied systematically in ways that indicated predominant droplet nucleation. 

Aqueous emulsions of styrene, methyl methacrylate, methyl acrylate, and ethyl acrylate were polymerized with y-radiation from a Co source in the presence of sodium dodecyl sulfate or sodium laurate. The continuous measurement of conversion and reaction rate was carried out dilato-metrically. The acrylates polymerized fastest and the over-all polymerization rate increased as follows styrene < methyl methacrylate < ethyl acrylate methyl acrylate. The effects of radiation dose, temperature, and original monomer and emulsifier concentrations were studied with respect to the following factors properties of polymer dispersions, number and size of polymer particles, viscometrically determined molecular weights, monomer-water ratio, and kinetic constants. 

Most emulsion polymerization is based on free-radical reactions, involving monomers (e.g., styrene, butadiene, vinyl acetate, vinyl chloride, methacrylic acid, methyl methacrylate, acrylic acid, etc.), surfactant (sodium dodecyl diphenyloxide disulfonate), initiator (potassium persulfate), water (18.2MQ/cm), and other chemicals and reagents such as sodium hydrogen carbonate, toluene, eluent solution, sodium chloride, and sodium hydroxide. 

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