Functionalized polymers with functional groups

Two ways of linking the PEG molecules are (1) PEG derivatives are obtained by reacting the PEG polymer with a group that is reactive with hydroxyl groups, e.g., anhydride, acid chloride, chloroformate or carbonate and (2) attachment of functional groups such as aldehydes, esters, amides etc. with the PEG polymer. 

Copolymers of styrene with 4-vinylpyridine (II) and N-viny1imizado1e (III) were obtained by copolymerization for one day at 60°C in 25 wt% comonomer solutions in toluene, using AIBN as initiator. In all cases the degrees of substitution, a, of the functionalized polymers with ligand groups were derived from the nitrogen contents found by elemental analyses. 

A series of poly(chloroalkyl ester)s (FI-26 to FI-28) can be employed for styrene polymerization with CuCl/L-1 to give polymers with ester groups at the a-end.158 Benzyl bromides FI-29317 and FI-30328 are another possibility for a-end functionalization. 

End-functionalized polymers with polymerizable groups such as double bonds and heterocycles of course provide macromonomers allyl, vinyl ester, vinyl ether, lactone, and epoxy are examples of such a category whose a-ends are not susceptible or have little susceptibility to metal-catalyzed radical polymerization. As discussed above, for example, allyl chloride and bromide (FI-33 and FI-34) are effective initiators to be used for styrene with CuCl and CuBr catalysts,161 while allyl compounds with remote halogens such as FI-35 and FI-36 allow the polymerization of methacrylates with high initiation effi-... 

There are of course, many facets of polymers for which our under-standing is far from complete. Polymers with associating groups bonded to their chains, polymer crystallization, liquid crystalline polymers and charged polymers are examples of areas of active research in polymer physics. These four particular examples are also very pertinent to understanding the functions of important biopolymers, such as DNA, RNA, proteins, and polysaccharides. By learning the fundamentals of chain conformations, thermodynamics, elasticity, and mobility, the readers of this book should be ready to consider these more challenging facets. 

Polyelectrolytes (polyanions or polycations) are an important class of functionalized polymers with charged groups attached to the chains [9-13]. The physicochemical behavior of these polymers is dominated by the attractive interactions between the fixed charges and counterions, and by the long-range repulsive interactions between the electric charges located on the macromolecular chains [63]. Electrostatic interactions between polymers and metal ions are found in many important biopolymers and... 

Polymers with polar groups can also be used as supports for single-site catalysts. Cross-linked polystyrene which has been chloromethylated, or acylated with CH3COCI—AICI3 then reduced with NaBH4 (Scheme 35), functions as a support for Et(Ind )2ZrCl2—... 

Methods of synthesizing polymers with carbonyl groups as supports of transition metal complexes have, moreover, been analyzed [104]. The activity of these catalysts in polymerization, oligomerization and hydrogenation reactions as a function of the polymer support structure has been discussed. 

Other examples of cationic HBP are the carbosilane polymers with ammonium groups on the surface synthesized by Gomez and de la Mata. The functionalization of a polycarbosilane matrix was carried out with peripheral allyl groups by two strategies (l) hydrosilylation of allylamines with carbosilane HBPs (PCS) containing terminal Si-H bonds, or (2) hydrosilylation of... 

Currently, anionic polymerization is regarded as one of the best methods available to prepare end-functionalized polymers. Vinyl polymers with haloalkyl groups at one chain end were prepared by anionic polymerization, followed by termination of the living anion with an excess of 1,2-dichloroethane or 1,4-dibromobutane [102]. These polymers served as macroinitiators for the polymerization of 2-methyl-2-oxazoline (MeOZO) and aromatic vinyl monomers (Scheme 11.27). 

An alternative approach to immobilize organic compounds such as MPC to metal substrates is the use of mussel-inspired chemistry. Mussels can rapidly and permanently adhere to all types of inorganic and organic surfaces in aqueous environments. Such adhesive properties rely on repeats of the 3,4-dihydro)q7-L-phenylalanine (DOPA) motif found in the foot protein of mussels. Although the exact mechanism of adhesion is not fully understood, it has been widely speculated that the 3,4-dihydro)qq3henyl (DHP) group of DOPA is responsible for the adhesion. When a polymer with DHP groups was placed in contact with a metal substrate, a thin polymer film was observed to spontaneously deposit on the surface. Functionalization of such a polymer was then able to impart new characteristics to the metal substrate. 

Pradellok, W., Vogl, O., and Gupta, A. (1981) Functional polymers. XIV. Grafting of 2(2-hydroxy-5-vinylphenyl) 2H-benzotriazole onto polymers with aliphatic groups, J. Polym. Sci., Polym. Chem. Ed., 19, 3307-3314. 

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