Side post-polymerization modification

Figure 31.4 The three distinct methods through which carbenes have been utilized for polymer synthesis. Type 1 Carbenes are essential to the polymerization process Type 2 Carbenes as side-group functionalities or reagents for post-polymerization modification Type 3 Carbenes are used as catalysts or ligands for polymerization catalysts.

Furthermore, a dialdehyde, a diisocyanide, and a carboxylic acid were applied in the Passerini one-pot polymerization (Scheme 4c). For this combination of reactants, Li et al. used adipaldehyde, 1,6-diisocyanohexane, and undecanoic acid, resulting in polyamides with functional side groups [35]. Optimization of the reaction conditions revealed that a IM chloroform solution of bifunctional components and a 2.2-fold excess of the carboxylic acid at 40°C gave the best results, yielding polymers with of up to 16.6 kDa in a yield of 90%. Here, m-alkene- or a)-alk5me-functionalized carboxylic acids were used as monomers in order to allow post-polymerization modifications via thiol-ene addition or copper-catalyzed azide-alkyne click chemistry (CuAAC). 

Abstract In this chapter, selected examples of sequential post-polymerization modifications are highlighted. Initially, we focus on side chain and chain end modifications in solution and at surface bounded polymers. Afterwards, the usage of this modifications as powerful tools in the synthesis of polymer structures such as graft and star polymers are discussed. 

Sequential reactions can be used for post-polymerization modifications. In this case, two general approaches are commonly used the polymer chain ends can be modified or the modification can take place at each repeating unit. We first focus on side chain modifications. Some of these reactions, which can be subdivided according to their functional groups, are discussed next. 

Scheme 3 Post-polymerization modification of epoxy side groups by thiol-epoxy leactirais and...

Apart from tuning the backbone and side chain, post-production is another feasible strategy for achieving high performance. " Post-polymerization modification is an attractive approach for preparation and optimization of conjugated polymers, allowing incorporation of functionality incompatible... 

The employment of click chemistry reactions in macromolecular science has allowed the rapid synthesis of a large array of polymers [42-51]. Indeed, the presence of clickable groups along the backbone, in the side chains, or at chain termini can be exploited for post-polymerization modifications (i.e., functionalization) leading to polymers bearing functionalities incompatible with the polymerization conditions [42]. 

Functionalization of polysilanes by chemical modification (post-polymerization) was covered in COMC II (1995) (chapter Organopolysilanes, p 101), where the formation of precursor polysilanes with potentially functionalizable side groups such as chloride, type 34 (via HCI/AICI3 chlorodephenylation of PMPS), 6 triflate, type 35 (via triflate replacement of phenyl groups)135,137 or alkyl halide (via chloromethylation of phenyl groups,138,139 type 36, or addition of HC1 or HBr to double bonds140) was discussed. Four other precursor polysilanes, which utilize the reactivity of the Si-Cl or Si-H bond, have been successfully applied in functionalization since COMC (1995) perchloropolysilane, 17 (see Section 3.11.4.2.2.(i) for synthesis),103 poly[methyl(H)silylene-f >-methylphenylsilylene],... 

Polymerization of modified monomers makes the polymerization itself more challenging, as polymerization parameters known for common monomers, such as copolymerization reaction rates, do not necessarily apply to pre-modified monomers. Post-polymerization functionahzation methods, however, enable the use of functionahties as the side-chain modifiers to a well-defined polymer backbone so that a variety of functional polymers can be produced through one single polymer scaffold. A major challenge of this method is that the modification step must be a clean... 

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