Lithium methacrylate

In the methacrylate series, sodium methacrylate reacts more rapidly than potassium methacrylate. Lithium methacrylate is entirely inert. Initially the polymerization of sodium methacrylate exhibits an accelerated reaction stage. 

The dielectric constant of poly(lithium methacrylate) dispersed in Cereclor oil at a volume fraction of 0,3 vs. the frequency of electric field under different shear rates is shown in Figure 7. The dielectric constant reaches a maximum value when Eq. (5) is satisfied. This phenomenon is called the FMP resonance between a shear field and an electric field. The flow field definitely has an influence on the particle polarization and hence on the dielectric constant. The dielectric constant thus becomes a function of both the shear rate and the frequency of the applied electric field. Especially when the flow field is rotational and strong enough to such an extent that the particle is able to spin, it may compete with the applied electric field for particle polarization. In other words, the particles or particle clusters can be orientated not only under an electric field, but also under a shear flow field. FMP was also observed in rigid or flexible polymer solutions [25-271. 

Kang W-C, Park H-G, Kim K-C, Ryu S-W (2009) Synthesis and electrochemical properties of lithium methacrylate-based self-doped gel polymer electrolytes. Electrochim Acta 54(19) 4540-4544, http //dx.doi.oig/10.1016/j.electacta.2009.03.050... 

After blending with P(MMA-lithium methacrylate) copolymer, the absorption ability and the ionic conductivity at low temperature are greatly improved, and the charge/discharge efficiency also increases. The cycling performance is better than that of the P(VDF-HFP) copolymer at high... 

Polymer blends are physical mixtures of two or more polymers and are commercially prepared by mechanical mixing, which is achieved through screw compounders and extruders. In these mixtures, different polymers tend to separate (instead of mixing uniformly) into two or more distinct phases due to incompatibility. One measure taken to improve miscibility is to introduce specific interactive functionalities on polymer pairs. Hydrogen-bondings have been shown to increase miscibility and, as a consequence, improve the strength of the blends. Eisenberg and co-workers have also employed acid-base interaction (as in sulfonated polystyrene with polyethylmethacrylate-Co-4-vinyl pyridine) and ion-dipole interaction (as in polystyrene-Co-lithium methacrylate and polyethylene oxide) to form improved blends. 

There are some indications that the situation described above has been realized, at least partially, in the system styrene-methyl methacrylate polymerized by metallic lithium.29 29b It is known51 that in a 50-50 mixture of styrene and methyl methacrylate radical polymerization yields a product of approximately the same composition as the feed. On the other hand, a product containing only a few per cent of styrene is formed in a polymerization proceeding by an anionic mechanism. Since the polymer obtained in the 50-50 mixture of styrene and methyl methacrylate polymerized with metallic lithium had apparently an intermediate composition, it has been suggested that this is a block polymer obtained in a reaction discussed above. Further evidence favoring this mechanism is provided by the fact that under identical conditions only pure poly-methyl methacrylate is formed if the polymerization is initiated by butyl lithium and not by lithium dispersion. This proves that incorporation of styrene is due to a different initiation and not propagation. 

The difficulties encountered in the early studies of anionic polymerization of methyl methacrylate arose from the unfortunate choice of experimental conditions the use of hydrocarbon solvents and of lithium alkyl initiators. The latter are strong bases. Even at —60 °C they not only initiate the conventional vinyl poly-addition, but attack also the ester group of the monomer yielding a vinyl ketone1, a very reactive monomer, and alkoxide 23). Such a process is described by the scheme. 

Polymerization of t-butyl methacrylate initiated by lithium compounds in toluene yields 100% isotactic polymers 64,65), and significantly, of a nearly uniform molecular-weight, while the isotactic polymethyl methacrylate formed under these conditions has a bimodal distribution. Significantly, the propagation of the lithium pairs of the t-Bu ester carbanion, is faster in toluene than in THF. In hydrocarbon solvents the monomers seem to interact strongly with the Li+ cations in the transition state of the addition, while the conventional direct monomer interaction with carbanions, that requires partial dissociation of ion-pair in the transition state of propagation, governs the addition in ethereal solvents. 

The polymerization of methacrylic esters, by lithium-organic initiators, carried out in toluene at low temperature, yields some stereocontrol46147 >. 

A salt of a polymer or copolymer of acrylic or methacrylic acid, in which the acid is neutralized with alkanolamines, alkylamines, or lithium salts [677], is suitable as a dispersing agent. 

Materials. Methyl methacrylate was a product of Rohm and Haas, and t-butyl methacrylate was obtained from Polvsciences, Inc. Potassium trimethylsilanolate (PTMS) was obtained from Petrarch Systems, Inc. Anhydrous lithium iodide, trimethylsilyl iodide (TMSI), and n-butyllit.ium (in hexanes) were purchased from Aldrich Chemical Co. 

In summary, we have examined several new methods for cleaving ester groups in poly(styrene-b-alkyl methacrylates). Short blocks of methyl methacrylate are very difficult to hydrolyze, but can be cleaved with reagents such as lithium iodide and potassium trimethylsilanolate. These latter reagents, however, result in side-reactions which appear to crosslink the polymer. 

The activity of transition metal allyl compounds for the polymerization of vinyl monomers has been studied by Ballard, Janes, and Medinger (10) and their results are summarized in Table II. Monomers that polymerize readily with anionic initiators, such as sodium or lithium alkyls, polymerize vigorously with allyl compounds typical of these are acrylonitrile, methyl methacrylate, and the diene isoprene. Vinyl acetate, vinyl chloride, ethyl acrylate, and allylic monomers do not respond to these initiators under the conditions given in Table II. 

Propylene-ammonia reaction, 10 135 Propylene-based routes, to methyl methacrylate, 16 251-252 Propylene carbonate, in lithium cells, 3 459... 

EMA ionomers (see Figure 4.30) are speciality thermoplastics copolymerized from ethylene and a small fraction of methacrylic acid, which is then transformed into the salt of sodium, zinc, lithium or another metal randomly distributed along the backbone. The backbone is identical to that of the polyolefins but the pendant groups are different, with a polar and ionic character. 

Gel polymer lithium-ion batteries replace the conventional liquid electrolytes with an advanced polymer electrolyte membrane. These cells can be packed in lightweight plastic packages as they do not have any free electrolytes and they can be fabricated in any desired shape and size. They are now increasingly becoming an alternative to liquid-electrolyte lithium-ion batteries, and several battery manufacturers. such as Sanyo. Sony, and Panasonic have started commercial production.Song et al. have recently reviewed the present state of gel-type polymer electrolyte technology for lithium-ion batteries. They focused on four plasticized systems, which have received particular attention from a practical viewpoint, i.e.. poly(ethylene oxide) (PEO). poly (acrylonitrile) (PAN). ° poly (methyl methacrylate) (PMMA). - and poly(vinylidene fluoride) (PVdF) based electrolytes. ... 

A 2-1. fouir-necked flask equipped with a sealed, Teflon-paddle stirrer, a merrcury thermometer, a gas inlet tube, and a dropping funnel is charged with 1.21. of anhydrous tetrahydrofuran (Note 1) and 50 g. (7.1-g. atoms) of lithium pieces (Note 2) under an atmosphere of prepurified nitrogen. The stirred mixture is cooled to —20° by means of a dry ice-acetone bath and a mixture of 100 g. (1.00 mole) of methyl methacrylate (Note 3), and 411 g. (3.0 moles) f n-butyl bromide (Note 4) is added dropwise over a period off 3-4 hours. During this addition, an exothermic reaction ensues which is controlled at —20° (Note 5), and on completion of the addition, the vessel is maintained at this temperature, with stirring, for an additional 30 minutes. The contents oF the flask are then liltered with suction through a... 

The same type of addition—as shown by X-ray analysis—occurs in the cationic polymerization of alkenyl ethers R—CH=CH—OR and of 8-chlorovinyl ethers (395). However, NMR analysis showed the presence of some configurational disorder (396). The stereochemistry of acrylate polymerization, determined by the use of deuterated monomers, was found to be strongly dependent on the reaction environment and, in particular, on the solvation of the growing-chain-catalyst system at both the a and jS carbon atoms (390, 397-399). Non-solvated contact ion pairs such as those existing in the presence of lithium catalysts in toluene at low temperature, are responsible for the formation of threo isotactic sequences from cis monomers and, therefore, involve a trans addition in contrast, solvent separated ion pairs (fluorenyllithium in THF) give rise to a predominantly syndiotactic polymer. Finally, in mixed ether-hydrocarbon solvents where there are probably peripherally solvated ion pairs, a predominantly isotactic polymer with nonconstant stereochemistry in the jS position is obtained. It seems evident fiom this complexity of situations that the micro-tacticity of anionic poly(methyl methacrylate) cannot be interpreted by a simple Bernoulli distribution, as has already been discussed in Sect. III-A. 

Several different nucleophilic substitution reactions have been observed in the polymerization of methyl methacrylate. Attack of initiator on monomer converts the active alkyl-lithium to the less active alkoxide initiator (Eq. 5-75). Further, methyl methacrylate (MMA) is converted to isopropenyl alkyl ketone to the extent that this reaction occurs. 

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