Chain length regulators

Larue, K., Kimber, M.S., Ford, R., Whitfield, C. Biochemical and structural analysis of bacterial O-antigen chain length regulator proteins reveals a conserved quaternary structure. J Biol Chem 284 (2009) 7395-7403. 

Morona, R., van den Bosch, L., Manning, P. Molecular, genetic, and topological characterization of O-antigen chain length regulation in Shigella flexneri. J Bacteriol 177 (1995) 1059-1068. 

Hydrogen is used as the chain length regulator in Ziegler-Natta polymerization. A proposed mechanism postulates that there exists a pre-established equilibrium of dissociative adsorption of hydrogen on TiCls catalyst surface as... 

The pol Tners s Tithesis is recommended to be carried out in inert gas atmosphere at temperatures 50-450 °C. If catalysts used are the salts of carbonic or hydrofluoric acids then oligomers appear. Chain length regulators when producing polyesterketones based on difluoro- or dichlorbenzophe-none and bisphenolates of alkali metals and dihydrox5maphthalenes can be the monatomic phenols [251-253],... 

With a highly developed interface surface, an essential part of copolymer macromolecules is on the surface, with the graft polystyrene in the matrix, which results in the observed decrease in the volume of dispersed particles as compared to the content of the graft copolymer (Table II, Sample 6). The further decrease of dispersed particles size intensifies the above-mentioned effect even more. For example, in the case of the particle size equalling 0.2 ]j (the polymer formed by the initiated copolymerization in the presence of the chain length regulator) out of 24% of the formed graft copolymer, only 11% are included in the volume of rubber particles. 

The reaction is often carried out in the presence of carboxylic adds and/or primary amines (e.g., acetic acid and hexane-1,6-diamine), which ad as chain length regulators. Consequently, the concentration of functional end groups is modified. 

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