Lithium alkyl amide, polymerization

Lithium Alkyl Amide as Initiator for Polymerizations of Isoprene and 1,4-Divinylbenzene... 

The ladder structures formed by lithium amides and their heavier group 15 analogues stand in contrast to those formed by the related lithium alkyls which generally prefer aggregates with three-dimensional or one-dimensional polymeric structures. 

Poly(amino acids)2892 and polypeptides2893 can also be grafted onto starch. Starch was first alkylated in the presence of lithium naphthalene, and then the alkoxy derivatives were reacted with /V-carboxy anhydrides. Poly(amide amines) were produced by reacting amines with dioic acids on starch and then crosslinking with epichlorohydrin or 1,2-dichloroethane 2894 Grafting of starch with a synthetic polymer chain, for instance, polystyryl carboxylate anions prepared by an anionic polymerization, can be carried out on a blend of starch and cellulose functionalized by sulfonation, mesylation, or tosylation. In this manner, cellulose-starch graft copolymers were prepared.2895... 

Alkah metal derivatives, including hydrides, alkyls and aryls, hydroxides, alkoxides, and amides, have been used as initiators for the anionic polymerization of epoxides. Sodium, potas-sirrm, and to a lesser extent cesium are the most often used alkali metals. Lithium derivatives are generally avoided since after the insertion of the first epoxide unit, they yield alkoxide species that are unable to properly propagate the polymerization, due to sUong association. Anionic polymerization of... 

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