Methacrylates, Table

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... 

The major one-carbon feedstock is methane and it serves as the feedstock to a number of important monomers including hexamethylene tetramine and melamine, used in the synthesis of a number of cross-linked thermosets as well as vinyl acetate, ethylene, ethylene glycol, and methyl methacrylate (Table 17.1). 

Polymethyl Methacrylate. Table 4 shows the results obtained for three commercially available polyraethyl methacrylate samples. Again the molecular weight averages obtained with SEC/Viscometry are in good agreement with the nominal values and the K and o values are self-consistent and in excellent agreement with the literature values.(40)... 

A similar improvement in sensitivity via copolymerization was observed in the copolymers of methyl methacrylate with a,a-dimethylbenzyl methacrylate (Table VI) and triphenylmethyl methacrylate (Table VII). In the former case the mechanism of sensitivity enhancement should be the same as that for the poly(a,a-diphenylethyl methacrylate-co-methyl methacrylate), although the enhancement of sensitivity with copolymerization is rather low. 

The copolymerisation of (J5), (36) and (38) was carried out with styrene (also terpoly-merisation with 1-vinylimidazole) and n-lauryl-methacrylate (Table Mixing of CO- copofymeiisation... 

Anionic poiymerization. Anionic polymerization is an addition polymerization in which the growing chain end bears a negative charge. The monomers suitable for anionic polymerization are those that have substituent groups capable of stabilizing a carbanion through resonance or induction. TVpical monomers that can be polymerized by ionic mechanisms include styrene, acrylonitrile, and methyl methacrylate (Table 14.20). 

Swelling of polymethyl methacrylate latex particles with methyl methacrylate. Table IV lists the swelling ratios and interfacial tensions for the different-size polymethyl methacrylate latexes with added Aerosol MA and sodium dodecyl sulfate emulsifiers. Comparison of the data with the theoretical curves from Model I (Figure 2) defines an apparent interaction parameter of 0.45 and the semi-empirical equation ... 

The kp value for phenyl methacrylate (Table 7) is smaller than that for methyl methacrylate (Table 8), although phenyl methacrylate is more likely to be attacked by a free radical than methyl methacrylate (see copolymerization data96 97 ). Accordingly, it is clear that the propagating radical of methyl methacrylate is more reactive than that of phenyl methacrylate. This is because the phenyl methacrylate radical is more likely to form the radical-solvent complex, which is consistent with the above-mentioned proposal by Henrici-01iv6 et al.67-71 and Bamford et al.2 . 

For the common nomenclature the usual practice is to name a polymer according to its source, i.e., the monomer(s) used in its synthesis, and the generic term used is poly monomer , whether or not the monomer is real. The prefix poly is added on to the name of the monomer to form a single word, e.g., polyethylene, polystyrene, and polyacrylonitrile (see Table 1.1). However, when the monomer has a multiworded name, the name of the monomer after the prefix poly is enclosed in parentheses, e.g., poly(vinyl chloride), poly(vinyl alcohol) and poly (methyl methacrylate) (Table 1.1). 

Copolymerization of ionic-type MCMs, alkali and alkaline earth metal salts, with various comonomers has been studied quite well. A detailed review of the basic studies has been given in a monograph [4] and they will not be analyzed in this book. Studies of the mechanism of copolymerization of such types of MCM were carried out in the case of organotin and -lead monomers. The widest recognition among these MCMs used as comonomers has been gained by trimethyl-, tributyl-, and triphenyltin methacrylates (Table 4-7) [4 and references therein]. 

Because of the attraction and repulsion forces, the conventionally determined intrinsic viscosity of mixtures of different polymers may appear higher or lower than that calculated from Equation (9-125) from the mass contributions w, and intrinsic viscosities [17], of the components. Examples of this are the values for mixtures of poly(styrene) and poly(methyl methacrylate) (Table 9-5). 

The hot strengths of the above comonomer system showed superior values when compared to the neat cured urethane methacrylate (Table 1). 

In principle, the chemical reactions of macromolecules should be similar to those of low-molecular-weight substances. Experimentally, however, either degradation is found to occur at very much lower temperatures or, occasionally, there is degradation into different products. The decomposition of poly(ethylene), for example, begins at 200°C lower than that of hexadecane. At 450°C, poly(methyl methacrylate) will be almost completely depolymerized into monomer, methyl methacrylate (Table 23-2). At this temperature, on the other hand, low-molecular-weight primary esters decompose into olefins and acids. The nature of the product also depends on whether the experiment is carried out at atmospheric pressure under nitrogen or under high vacuum (Table 23-3). 

PROBLEM 14.6 Methyl methacrylate (Table 14.1) can be polymerized by catalytic amounts of n-butyllithium at -78°C. Using eqs. 14.17 and 14.18 as a model, write a mechanism for the reaction. Show how the intermediate carbanion is resonance-stabilized. 

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