Cation charge density

The protonated form of poly(vinyl amine) (PVAm—HCl) has two advantages over many cationic polymers high cationic charge densities are possible and the pendent primary amines have high reactivity. It has been appHed in water treatment, paper making, and textiles (qv). The protonated forms modified with low molecular weight aldehydes are usehil as fines and filler retention agents and are in use with recycled fibers. As with all new products, unexpected appHcations, such as in clear antiperspirants, have been found. It is usehil in many metal complexation appHcations (49). 

Bancroft and Gesser [870] conclude that kinetic factors are predominant in determining whether decomposition of a metal bromate yields residual bromide or oxide. The thermal stabilities of the lanthanide bromates [877] and iodates [877,878] decrease with increase in cationic charge density, presumably as a consequence of increased anionic polarization. Other reports in the literature concern the reactions of bromates of Ag, Ni and Zn [870] and iodates of Cd, Co, Mn, Hg, Zn [871], Co and Ni [872], Ag [864], Cu [867], Fe [879], Pb [880] andTl [874]. 

The protonated form of poly(vinyl amine) (PVAm-HCl) has two advantages over many canonic polymers high cationic charge densities are possible and the pendent primary amines have high reactivity. It has been applied in water treatment, paper making, and textiles. 

The thermal stabilities of the lanthanide bromates and iodates [43] decrease with increase in cationic charge density, presumably as a consequence of increased anionic polarization. Metallic lead reacts [44] with K, Ca and Ba iodates to yield the iodites at about 700 K ... 

Finally, one might predict that rigorously controlled experiments could reveal a trend in catalytic activity in the presence of proton donors correlating with cation charge density, similar to that reported by the Linde group 40,48), wherein the effect of the cation would be mediated through the protons. This effect is analogous to that of various... 

By virtue of their cationic nature, the above polymers are very substantive to hair. As a result of multiple points of electrostatic attachment to the hair fiber, they are also difficult to remove completely, especially when charge density is high [29,46], It has been reported that deposition of many polymers on hair is inversely proportional to cationic charge density [48,49], This was explained by the observation that smaller quantities of high-charge-density polymers would be needed to neutralize all of the negative charge on a hair fiber. 

The interaction with the cation noticeably affects the reactivity of the anion in media of low dielectric constant. Thus, on switching from the large tetra u-butylammonium to the small lithium cation, the reactivity sequence of the corresponding halides in the nucleophilic substitution of n-butyl 4-bromobenzenesulfonate in the weakly dissociating acetone is completely reversed (Eq. 3). Whereas the order obtained with bulky quaternary onium salts (Cl >Br >I ) corresponds to that of free, nonassociated halides in dipolar non-HBD solvents (e.g.. acetone), the sequence of the lithium halides (Cl
protic solvents, is mainly due to the increasing deactivation of the anion in the ion pair on increasing the cation charge density ... 

A major drawback of nanopartides formulated using cationic polymers that has limited thdr progress toward use in dinical trials is toxidty. Although the molecular basis of toxidty is undear, the polycationic nature of the polymers appears to be the main origin of toxidty. Thus, recent efforts to devdop polymers with reduced toxidty have focused on low-MW polymers, biodegradable polymers, and polymers with reduced cationic charge density. 

Incorporated multivalent complex anions in PXV matrix were desorbed by the decrease of cationic charge density of PXV. About half or all of cationic charges of PXV were reduced when potentials were stepped to -0.70 V and -1.20 V, respectively. At -0.70 V, Fe(CN)0 " was desorbed theoretically (about 50%), but desorption efficiency of Mo(CN)84 at -0.70 V was half as much as that of Fe(CN)0 system. This might correspond to the strength of the interaction between PXV matrix and complex anions, or the hydrophobicity of Mo(CN)8. ... 

Polyacrylamide copolymer PAA (medium or HMW) The cationic charge density of the polymer affected initial flocculation as well as reflocculation fiber fines and filler responded differently on flocculation [18]... 

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