Polymerization quaternary ammonium cationic monomers

To synthesize water-soluble or swellable copolymers, inverse heterophase polymerization processes are of special interest. The inverse macroemulsion polymerization is only reported for the copolymerization of two hydrophilic monomers. Hernandez-Barajas and Hunkeler [62] investigated the copolymerization of AAm with quaternary ammonium cationic monomers in the presence of block copoly-meric surfactants by batch and semi-batch inverse emulsion copolymerization. Glukhikh et al. [63] reported the copolymerization of AAm and methacrylic acid using an inverse emulsion system. Amphiphilic copolymers from inverse systems are also successfully obtained in microemulsion polymerization. For example, Vaskova et al. [64-66] copolymerized the hydrophilic AAm with more hydrophobic methyl methacrylate (MMA) or styrene in a water-in-oil microemulsion initiated by radical initiators with different solubilities in water. However, not only copolymer, but also homopolymer was formed. The total conversion of MMA was rather limited (<10%) and the composition of the copolymer was almost independent of the comonomer ratio. This was probably due to a constant molar ratio of the monomers in the water phase or at the interface as the possible locus of polymerization. Also, in the case of styrene copolymerizing with AAm, the molar fraction of AAm in homopolymer compared to copolymer is about 45-55 wt% [67], which is still too high for a meaningful technical application. 

The Polymerization of Quaternary Ammonium Cationic Monomers with Acrylamide... 

Very frequently non-optimal setpoint trajectories are used for controlling reactor temperatures in batch reactors [25,39,179,180]. Reactor temperatures maybe allowed to increase from ambient temperatures up to a maximum temperature value, in order to use the heat released by reaction to heat the reaction medium and save energy (reduce energy costs). The temperature increase is almost always performed linearly, because of hardware limitations and simplicity of controller programming. After reaching the maximum allowed temperature value, reactor temperature is kept constant for a certain time interval, for production of polymer material at isothermal conditions. At the end of the batch, the reaction temperature is increased in order to reduce the residual monomer content of the final resin, usually with the help of a second catalyst. Heuristic optimum temperature trajectories were also formulated for batch polymerizations of acrylamide and quaternary ammonium cationic monomers, in order to use the available heat of reaction [181]. The batch time was split into two batch periods an isothermal reaction period and an adiabatic reaction period. 

Definition Polymeric quaternary ammonium salt consisting of acrylamide and dimethyl diallyl ammonium chloride monomers Formula (CsHieN C3H5NO Cl)x Properties Dens. 1.020 ref. index 1.350 (20 C) cationic... 

Kurokawa et al. [258-260] developed a novel but somewhat complex procedure for the preparation of PP/clay nanocomposites and studied some factors controlling mechanical properties of PP/clay mineral nanocomposites. This method consisted of the following three steps (1) a small amount of polymerizing polar monomer, diacetone acrylamide, was intercalated between clay mineral [hydrophobic hectorite (HC) and hydrophobic MMT clay] layers, surface of which was ion exchanged with quaternary ammonium cations, and then polymerized to expand the interlayer distance (2) polar maleic acid-grafted PP (m-PP), in addition was intercalated into the interlayer space to make a composite (master batch, MB) (3) the prepared MB was finally mixed with a conventional PP by melt twin-screw extrusion at 180°C and at a mixing rate of 160 rpm to prepare nanocomposite. Authors observed that the properties of the nanocomposite strongly dependent on the stiffness of clay mineral layer. Similar improvement of mechanical properties of the PP/clay/m-PP nanocomposites was observed by other researchers [50,261]. 

Another mode of termination by monomer, which has been suggested for the polymerization of N-vinylcarbazole, is formation of a quaternary ammonium ion from the growing cation and the monomer [25] which is essentially the same as reaction (XIa). 

Free radical polymerizations may also be used to synthesize a host of cationic polyelectrolytes. Diallyl quaternary ammonium salts such as dimethyl-diallylammonium chloride, diallyldiethylammonium chloride, and diallylmethyl b-propionamido chloride are an interesting class of monomers which will... 

Poly(diallyldimethylammonium chloride) was the first quaternary ammonium polymer approved for potable water clarification by the United States Public Health Service, and has historically been the most widely produced cationic polyelectrolyte. There have been several studies on the kinetics (26-37) and uses of diallyldimethylammonium chloride (DADMAC) (38-45) however, there have been no investigations in inverse microsuspension, the most common industrial method of polymerization. Furthermore, there is considerable disagreement between published reactivity ratios, probably because no satisfactory analytical methods have been described in the literature for residual monomer concentration or copolymer composition. For other commercially important quaternary ammonium polymers, such as dimethylaminoethyl methacrylate and dimethylaminoethyl acrylate, few kinetic data are available (46-51) only Tanaka (37) measured the reactivity ratios. 

In comparison to the previously discussed monomers, the polymerization of N-substituted aziridines is easier to control since the side reactions by proton transfer are eliminated because of the absence of primary and secondary amines. Nonetheless, termination by nucleophilic attack of the cationic propagating chain end into polymeric tertiary amines results in the formation of unreactive quaternary ammonium groups, that is, termination. As a result, the polymerization of N-substituted aziridines usually stops at limited conversion as was first demonstrated for A-methylaziridine by Jones [129]. Detailed evaluation of the polymerization kinetics as well as the evolution of molar mass during the polymerization revealed that termination mainly occurs via intramolecular backbiting... 

The cationic copolymerization was carried out in air at 25°C in a nitrobenzene solution using stannic bromide as catalyst, while the anionic polymerization was studied in air with sodium dissolved in anunonia [186]. Although many monomers may be polymerized by quaternary ammonium salts, vinyl acetate does not produce any polymer on treatment with dimethylphenylbenzylammonium chloride [187]. 

Similar to the biguanide structures, Dizman et al. created l,4-diazabicyclo[2.2.2]octane (DABCO)-based stmctures carrying two quaternary ammonium charges with butyl and hexyl alkyl extensions (C12). The monomer was assembled by multiple nucleophilic substitution reactions. Polymers were formed by free radical polymerization in water. These polymers, much like the biguanide acrylate and pyridinium polymers, combined hydrophobidty and cationic charge on the same monomer. One difference is that the cationic charge was also separated from the backbone of the polymer by a long alkyl chain. As with the pyridine polymers, the hexyl alkyl monomers were found to be the most effective biocides. 

Further work by Palermo and Kuroda extended the library of molecules to indude tertiary amine- and quaternary ammonium-fimctionalized methacrylates. For this series, cationic monomers were polymerized with methyl and butyl acrylate monomers. As with the styrene-based polymers of Gelman et al, the quaternary ammonium series was much less antimiaobial and somewhat less hemolytic than the primary and tertiary amine series. Again, titration of the polymers showed that there is partial deprotonation of the amine functionalities at neutral pH. The deprotonated moieties are more hydrophobic than the ammonium salts, and thus inaease the membrane activity of the polymers. No explanation was given, however, for the inaeased activity of the primary amine polymers over the tertiary amine polymers. 

Cationic polymers include homopolymers and cationic copolymers obtained by the polymerization of a vinylic monomer with a quaternary ammonium group or a quatemized amine with another soluble monomer in water such as acrylamide and methacrylamide. The most frequently used polymers are those derived from gum guar such as guar hydroxyl propyl triamonium chloride. They are sold under the trade names Jaguar C13S, C17, etc. [12-16]. 

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