Polymerization of ethyl

The molecular weights of the polymers are much larger than would be predicted from the monomer/initiator ratio, as seen in Fig. 4. However, this effect is most evident for the polymerization of ethyl cyanoacrylate alone. 

Strohmeier and Hartmann [14] first reported in 1964 the photoinitiation of polymerization of ethyl acrylate by several transition metal carbonyls in the presence of CCI4. Vinyl chloride has also been polymerized in a similar manner [15,16] No detailed photoinitiation mechanisms were discussed, but it seems most likely that photoinitiation proceeds by the route shown in reaction Scheme (9). 

The organolanthanide initiators allowed stereospecific polymerization of ethyl, isopropyl, and t-butyl methacrylates (Table 3). The rate of polymerization and the syndiotacticity decreased with increasing bulkiness of the alkyl group in... 

In 1970, a patent by Fukui and coworkers cited the cationic polymerization of ethyl vinyl ether in liquid C02 [85]. In these reactions, SnCl4 or ethyl etherate of boron trifluoride were employed as the catalysts and the polymerizations were conducted for 20 hours at room temperature to conversion of greater than 90% polymer. No molecular weight data or spectra for these polymers were reported in this work. 

Items b and d may be related since the decrease in rate begins to be observed at about 40% conversion, i.e. at the point where [AN] has fallen to about 2.25 M. It is interesting to note that we ( ) and others ( 5) have also noted very slow rates of polymerization of ethyl acrylate at 1 M concentrations in ethyl acetate using either tetrabutyl ammoniurn bromide or 18-crown-6 as the phase transfer catalyst. Further studies in this area are needed. 

Fig. 31. Polymerization of ethyl acrylate by wool swelling at 25° C using water as a swelling agent (60% aquesous emulsion with 3.2% Triton X-405) (105)...

The enolate species 2, derived from methacrylates with bulkier ester groups than MMA, are sterically protected against the access of BujAl under the above-mentioned conditions, even when the porphyrin moiety is a non-ortho-substituted tetraphenylporphyrin. An example is shown by the polymerization of ethyl methacrylate (EMA) using 1 (X=Me) as an initiator, where the growing species have an EtO group in the terminal enolate unit 2 (R=Et). After the addition of BujAl to the system, polymerization proceeded to 100% monomer conversion within 10 min. The Mn of the produced polymer was close to the expected value, and the MWD was narrow (Table 5, run 5). A similar result was obtained for the polymerization of isopropyl methacrylate (PMA) with the 1 (X= Mel- soBujAl system, which quantitatively gave a narrow MWD poly(methacr-ylate) with a predicted Mn (Table 5, run 6). 

Polymerizations of acrylic and methacrylic esters are highly exothermic (e.g., A//polymeriZation of ethyl acrylate is 13.8 kcal/mol [2]). Generally, the heats of polymerization of acrylates are greater than those of methacrylates. 

Example C-tn-18 AE(50EO) for t ie emulsion polymerization of ethyl acrylate... 

Most of the reported polyfvinyl ether) macromonomers have been prepared with a methacrylate end group which can be radically polymerized and which is non-reactive under cationic polymerization conditions [71-73]. Generally, the synthesis was based on the use of the functional initiator 30, which contains a methacrylate ester group and a function able to initiate the cationic polymerization of vinyl ethers. Such initiator can be obtained by the reaction of HI and the corresponding vinyl ether. With initiator 30 the polymerization of ethyl vinyl ether (EVE) was performed using I2 as an activator in toluene at -40 °C. The MW increased in direct proportion with conversion, and narrow MWD (Mw/Mn= 1.05-1.15) was obtained. The chain length could be controlled by the monomer to initiator feed ratio. Three poly(EVE) macromonomers of different length were prepared by this method Mn=1200,5400, and 9700 g mol-1. After complete... 

B. Living Cationic Polymerization of Ethyl Vinyl Ether with the... 

An interesting characteristic of mthenocene is that it is a photoinitiator for the anionic polymerization of ethyl 2-cyanoacrylate. Solutions with millimolar concentrations of the complex in neat cyanoacrylate polymerize to a hard, plastic solid within seconds upon exposure to light. The low concentration of mthenocene required for the polymerization makes it desirable in applications such as coating and adhesives that require solvent-free solutions of monomer. ... 

In all such cases the process initiated by persulfate begins in the aqueous phase with the formation of water-soluble, surface-active polymeric radicals which, after growing to a certain critical size, precipitate to form particles subsequent polymerization proceeds mainly within these particles. The higher the solubility of the monomer in water, the more surface-active radicals and therefore primary particles are formed and the higher the stability and the concentration of the latex, A kinetic curve of the emulsifier-free polymerization of ethyl acrylate confirming this scheme is shown by Curve 1 in Fig. 3 (Yeliseyeva and Petrova, 1970). The process... 

Fig. 10, Variation of the number of partides during polymerization of ethyl acrylate in the presence of emulsifiers (i) sodium alkylsulfonate (2) oxyethylated (30) cclyl alcohol and (3) AAOES. Recipe m.p. ethyl acrylate, lOO emulsifier, AO ammonium persuUate. 0.5 water.

Fie, 21. Dependence of overall surface of particles ( ) on conversion during polymerization of ethyl acrylate. SDDS 1.04 xiO mcj/dm ammonium persulfate 0.44 X 10 moVdm phase ratio, 1 9 i 45°C. 

PPL catalyzed the polymerization of methyl esters of 5-hydroxypentanoic and 6-hydroxyhexanoic acids.149 In the polymerization of the latter in hexane at 69 °C for more than 50 days, the polymer with DP up to 100 was formed. Relationships between solvent type and polymerization behaviors were systematically investigated hydrophobic solvents such as hydrocarbons and diisopropyl ether were suitable for the enzymatic production of high molecular weight polymer. Pseudomonas sp. lipase catalyzed the polymerization of ethyl esters of 3- and 4-hydroxybu-tyric acids, 5- and 6-hydroxyhexanoic acids, 5-hy-droxydodecanoic acid, and 15-hydroxypentadecanoic acid.157 Oxyacid vinyl esters were demonstrated as new monomers for polyester production under mild reaction conditions, yielding the corresponding polyesters with A/n of several thousands.276... 

Table 1 Polymerization of ethyl isocyanide in the presence of Ni(acac)2 (ca. 2 mol%)...

The superior catalytic activity of Ni catalysts over other transition metal complexes was proven by a comparison of a series of metal acetylacetonates as catalysts for the polymerization of ethyl isocyanide in chloroform (Scheme 14) [15]. Fe(acac)3, Mn(acac)2, Zn(acac)2, and Cd(acac)2 showed either no, or an extremely low, catalytic activity, whereas Cr(acac)3 and Co(acac)3 afforded almost 10% yield of poly (isocyanide). Co(acac)2, Pd (acac)2, and Cu(acac)2 exhibited moderate activity, resulting in the formation of the polymer in 29-61% yields. Ni(acac)2 showed almost the same catalytic activity as Co2(CO)8, whose remarkable catalytic activity had already been established by Yamamoto et al. [5]. 

QUIRK AND SEUNG Anionic Polymerization of Ethylate Oxide... 

Macroradicals were obtained by the polymerization of ethyl acrylate in cyclohexane, styrene in hexane, vinyl acetate in decane, and methyl methacrylate in hexane. Because of the solubility of the vinyl acetate block in hexane, the ratio of the weight of vinyl acetate to that of the macroradical in poly (methyl methacrylate-b-vinyl acetate) after heating at 50°C for three days was only 30/100. By contrast, because of the insolubility of the acrylonitrile block in hexane, good yields of methyl methacrylate-b-acrylonitrile macroradicals were obtained. The ratio of the weight of the acrylonitrile block to that of the macroradical was thus 90/100 after heating the mixture for three days at 50°C in hexane. 

Similar techniques have been used to incorporate silica into various polymers. (Mineral fillers are often given hydrophobic coatings to help in their dispersion in polymers such as polyolefins.60) Methacrylatopropyltrimethoxysi-lane has been used to add the methacrylate group on to silica. The treated silica was used in the emulsion polymerization of ethyl acrylate.61 Transparent films could be formed from the product. Living polystyrene was end-capped with a triethoxysilane (5.20), after which it was used to treat silica and alumina.62... 

Banthia et al. [44] first performed the polymerization of ethyl hexyl acrylate in DEP conditions (Table 6) but without using any solvent. The calculated carboxy functionalities were around 2 and the molecular weights were about 104. The number-average molar masses (Mn) were unexpectedly high for DEP conditions and were probably due to the bulk conditions. 

The relevance of the carbocationic mechanism was also demonstrated for the polymerization of ethyl vinyl ether by end-group analysis following termination with aqueous methanol. An aldehydic resonance (d 9.8) was observed in the H NMR spectrum of the resulting polymer, the aldehyde functionality arising from hydrolysis of the acetal formed via nucleophilic attack by methanol on the active site of the growing polymer (eqs 17 and 18). 

The complex of unknown structure formed on treating Ti(CH2Ph)4 with [Ph3C][B(C6Fs)] is also a good initiator for the polymerization of ethyl vinyl ether and AAvinylcarbazole but has not been studied in detail. ... 

Polymerization of bis[ -(allyloxycarbonyl)phenyl] esters of aliphatic and aromatic dicarboxylic acids to produce highly cross-linked polymers witii good optico-mechanical properties [126]. This study should be compared with the more recent work of Ref. [80a] on the polymerization of ethyl a-[(allyloxy)methyl]acrylate. 

Table 12. Polymerization of ethyl methacrylate in toluene by BuLi at various tonperatures for24hr .Rrf." )...

Scheme 10.15 Photoinitiation of the polymerization of ethyl 2-cyanoacrylate by potassium reineckate [57].

It was argued that the MLCT excited state has a change in hapticity (from if to rf), and this facilitates solvent attack on the Fe center, leading to loss of a CpR ligand. The anion thus produced efficiently initiates the anionic polymerization of ethyl a-cyanoacrylate. It was likewise shown that cationic polymerizations could be initiated by LF excitation of CpFe( 7 -arene) complexes. 

Kutal has reported that MLCT excitation of benzoyl-substituted ruthenocenes leads to anionic polymerization of ethyl 2-cyanoacrylate (Equation (31)). These complexes do not undergo ligand loss as a result of MLCT excitation, and it was suggested that the charge redistribution in the excited state allowed the complex to act as an anionic initiator. 

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