Amination reactions polymer synthesis

In spite of the relatively low performance/cost ratio of the respective products, application of reactions on polymers are of continuous interest for synthesis of amine functionalized polymers. The technique of modification of solid polymers by exploitation of their reactive moieties under heterogeneous conditions allows properties to be tailored and optimized according to specific needs and requirements. Telechelic polymers are used for the synthesis of materials with predictable and controlled properties. Application of carefully designed macromolecules provides systems with functional groups dispersed along the polymer chain or bond at the end of macromolecules. 

New kinetic regularities at polymerization of vinyl monomers in homophase and heterophase conditions in the presence of additives of transition metal salts, azonitriles, peroxides, stable nitroxyl radicals and radical anions (and their complexes), aromatic amines and their derivatives, emulsifiers and solvents of various nature were revealed. The mechanisms of the studied processes have been estabhshed in the whole and as elementary stages, their basic kinetic characteristics have been determined. Equations to describe the behavior of the studied chemical systems in polymerization reactions proceeding in various physicochemical conditions have been derived. Scientific principles of regulating polymer synthesis processes have been elaborated, which allows optimization of some industrial technologies and solving most important problems of environment protection. 

To prepare the leading end-modified polymers for in vivo use, a modified protocol was used to remove all solvent and unreacted monomer. The initial synthesis of the base PBAE was the same. Then, for the end-capping reaction, THF was used as a solvent rather than DMSO. Diethyl ether was used to precipitate the polymer and extract unreacted amines. All polymers were dried and then dissolved in DMSO before use. 

There are four different chemical reactions that have been used to crosslink polymers with peptide sequences (Fig. 6.8) (i) amide bond formation (ii) Michael-type addition (iii) Huisgen cycloaddition (click reaction) and (iv) radical polymerisation. The amide bond formation follows typical solid phase peptide synthesis (SPPS) protocols and does not require functionalisation of the termini of the peptide sequence. Fluorenyhnethoxycarbonyl (Fmoc) protection of the N-terminus allows attachment of the peptide sequence to an amine-bearing polymer. After removal of the Fmoc group, the amine-terminated peptide-polymer conjugate can be reacted with a second polymer bearing carboxylic acid functionalities using the same coupling chemistry (Maier et al, 2011). For Michael-type additions the peptide... 

While much of our effort involves the synthesis of organotin polyamines from reaction with diamines, organotin polymers have been synthesized from reaction with preformed amine-containing polymers. Using polyethyleneimine, the products will be linear as the monohalo organotin is reacted with the polyethyleneimine, 10, but they will be cross-linked when dihaloorganotin reactants with two functional groups are employed, 11. 

The functional groups from the starting monomers may be further modified either by click chemistry, such as thiol-ene, epoxy-amine reaction and copper catalyzed azide-alkyne cycloaddition. Authors also applied the Passerini synthesis pathway to a mixture of the three initial monomers to obtain a combined photodegradable polymer with triple functionality (P4) (Scheme 4). Reproduced with permission. Copyright 2014, American Chemical Society [3]. The photocleavable character may be determined by UV-Vis and gel permeation chromatography (GPC) techniques, when the polymers cleave into the corresponding ortho-nitrosobenzaldehydes and carboxylic acids. 

The employment of MCRs is expected to overcome the drawbacks of click reactions because many MCRs proceed with common functional compounds such as aldehydes, ketones, and amines, which are commercially available in most cases. Hence, polymer chemists are currently examining and starting to take advantage of the synthetic utility of MCRs for polymer synthesis [42, 43]. Although the main MCRs used in polymer science are isocyanide-based reactions such as the Passerini and Ugi reactions, this chapter will focus on metal-catalyzed MCRs in the area of polymer chemistry. 

Considering the practical importance of isocyanide-free MCRs, metal-catalyzed multicomponent reactions (MC-MCRs) are ideal candidates for polymer synthesis. Among the growing number of MC-MCRs, the three-component reaction between amines, aldehydes, and acetylenes (A -coupling) should be addressed. A -coupling... 

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