تفاعل #668368
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The dendrimers selected for the toner additives of the present invention are, for example, illustrated in the documents mentioned herein. Dendrimers are known, and can be considered radially symmetrical molecules of a STARBURST™ topology comprised of an initiator core, such as nitrogen, ethylenediimine, silicon, and the like, interior layers attached to the core and comprised of, for example, three, four or more arms, each arm being composed of repeating units with the number of repeating units in each arm being considered the generation of the dendrimer, and terminal covalently bonded stable free radical functional groups, such as for example a nitroxyl compound attached to the outermost generation, which dendrimers having related terminal amine terminated groups are illustrated, for example, in U.S. Pat. Nos. 4,507,466; 4,631,337; 4,558,120; 4,568,737 and 4,587,329; and in D. A. Tomalia, A. M. Naylor, and W. A. Goddard III, Angewandte Chemie, Int. Ed. Engl.,29, 138 (1990), the disclosures of which are totally incorporated herein by reference. The size and shape of the STARBURST™ dendrimer molecule and the functional groups present in the dendrimer molecule can be controlled by the choice of the initiator core, the number of generations, and the choice of repeating units employed at each generation. The choice of the dendrimer components can affect the properties of the dendrimers. The initiator core type can affect the dendrimer shape producing, for example, spheroid-shaped dendrimers, cylindrical- or rod-shaped dendrimers, or ellipsoid-shaped dendrimers. Sequential building of generations determines the dimensions of the dendrimers and the nature of its interior. Examples of core materials which have been successfully used include ammonia, polyfunctional alcohols, such as pentaerythritol or tris-(hydroxymethyl)ethane, 1,1,1-tris-(4-hydroxyphenyl)-ethane, polyfunctional amines, such as ethylene diamine, linear polyethyleneimines, and the like, carbosilanes such as tetravinylsilane as described, for example, in J. Roovers, P. M. Toporowski and L-L. Zhou, Polymer Preprints, American Chemical Society, Division of Polymer Chemistry, 33, (1), 182 (1992), and the like; polysiloxysilanes, such as those described, for example, in L. J. Mathias and T. W. Carothers, J. Am. Chem. Soc., 113, 4043 (1991), in H. Uchida, Y. Kabe, K. Yoshino, A. Kawamata, T. Tsumuraya, and S. Masamune, J. Am. Chem, Soc., 112, 7077 (1990), in A. Morikawa, M. Kakimoto, and Y. Imai, Macromolecules, 24, 3469 (1991), and the like; polyfunctional aromatic rings, such as benzoic acids, such as 3,5-diacetoxybenzoic acid, as illustrated, for example, in B. I. Voit and S. R. Turner, in Polymer Preprints, American Chemical Society, Division of Polymer Chemistry, 33, (1), 184 (1992); hyperbranched polyphenylenes such as those described by Y. H. Kim and O. W. Webster, in J. Am. Chem. Soc., 112, 4592 (1990), hyperbranched polyarylenes, such as those described in U.S. Pat. Nos. 4,857,630 and 5,070,183 to E. I. DuPont de Nemours and Company, and the like. The chemical functionality of the repeating unit in the interior layers can include, for example, amidoamines, such as amino-ethyl acetamide, imines, such as diethylene diimine, ethers such as those obtained from materials such as, for example, 3,5-dihydroxyethyl benzyl alcohol, siloxanes, such as dimethylsiloxane, diethylsiloxane, diphenylsiloxane, and the like, carbosilanes, such as ethyl silane and the like. The terminal functionalities include, for example, amino groups, quaternary ammonium salts, phosphonium salts, hydroxyl groups, carboxylic acid groups, carboxylates, esters, amides, phosphates, sulfonates, and the like. The synthesis of dendrimers usually occurs by a linear, convergent, or divergent aproaches. The divergent approach involves the initial reaction of a monomer with the initiator core, followed by exhaustive reaction of the resulting functional groups with a difunctional compound, such as a diamine, including, for example, ethylene diamine, to afford the next generation of reactive amino groups. Repetition of the two-step procedure leads to subsequent generations. An alternate synthetic route uses a convergent growth synthesis as described in detail in C. J. Hawker and J. M. J. Frechet, J. Am. Chem. Soc., 112, 7638 (1990), the disclosure of which is totally incorporated herein by reference. Examples of dendrimers prepared by the divergent method include STARBURST® dendrimers available from the Michigan Molecular Institute, Dendrimer Microparticles available from Polysciences, Inc., in which the terminal functional groups are primary amino groups, and which range in average diameter of from about 10.8 Angstroms (first generation) to about 83.9 Angstroms (8th generation). Other dendrimers of interest, in embodiments, of the present invention include those as illustrated in U.S. Pat. Nos. 5,041,516; 4,857,599 and 4,694,064, the disclosures of which are totally incorporated herein by reference.