Functionalisation of polymers

A novel approach is used to compatibilise a blend without addition of premade copolymers or functionalisation of polymers lacking functional groups. Solid-state shear pulverisation (S3P) processes polymers at temperatures below the melt transition (for semicrystalline polymers) or the glass transition (for amorphous polymers). The polymer, introduced as pellets or flakes into the pulveriser. 

The future trend of nanofibre development may include modification toward functionalisation of polymer nanofibres intended to improve their performance and function in biomedical applications. This purpose is achieved by incorporating such therapeutic agents as antibacterial agents and growth factors into the nanofibrous structures, so that the product will duly become capable of infection control, with improved biocompatibility and promotion of cell proliferation and differentiation. 

C. H. Bamford, K.G. Al-lamee, (University of Liverpool) Functionalisation of polymers. US Patent 5618887, April 1997. 

Table 13. Effect of the level of functionalisation of polymer 200 on activity and...

Great Lakes has reported that functionalisation with graftable moieties results in a product which can be chemically bound to a polysiloxane backbone, e.g. Silanox MD. Functionalisation of polysiloxanes with HALS (polymer-bound HALS, P-HALS) and phenolic antioxidants has been described [22]. Functionalised polysiloxanes (Figure 3.23) exhibit high stabilisation activity in critical applications such as PP fibres and PE cables [58]. 

In the absence of oxygen or any other radical trap, however, mechanochemically formed macroalkyl radicals (scheme I, I) can be made to react with chemically reactive modifiers, RM, (see scheme Id) this forms the basis of an in-situ synthesis of polymer adducts i.e., the functionalised additive/modifier becomes chemically bound onto the polymer backbone. 

Addition reaction of peroxide-generated macroalkyl radicals with the reactive unsaturation in MA is shown in reaction scheme 4. The functionalised maleic-polymer adduct (II, scheme 4) is the product of hydrogen abstraction reaction of the adduct radical (I, scheme 4) with another PP chain. Concomitantly, a new macroalkyl radical is regenerated which feeds back into the cycle. The frequency of this feedback determines the efficiency of the cyclical mechanism, hence the degree of binding. Cross-linking reaction of I occurs by route c ( scheme 4). 

Figure 26 hi NMR spectrum from MDI/PPG polyurethane prepolymer. Inset shows expansion of spectrum indicating assignment for functionalised end groups of polymer. 

The synthesis of both enantiomers of vasicinone has been carried out using almost entirely polymer-supported reagents. The route was based on functionalisation of deoxyvasicinone by a highly selective bromination then via enantioselective reduction of the derived ketone <06SL2609>. 

Frechet JMJ, Nuyens LJ (1976) Use of polymers as protecting groups in organic synthesis. III. Selective functionalisation of polyhydroxy alcohols. Can J Chem 54 926-934... 

The first published report on the use of this catalyst for the cross-metathesis of functionalised acyclic alkenes was by Blechert and co-workers towards the end of 1996 [37]. This report was also noteworthy for its use of polymer-bound alkenes in the cross-metathesis reaction. Tritylpolystyrene-bound AT-Boc N-al-lylglycinol 18 was successfully cross-metathesised with both unfunctionalised alkenes and unsaturated esters (Eq. 17) (Table 1). 

New Orleans, La., August 1999, p.752-3 POLYSTYRENE/POLYPROPYLENE POLYMER BLEND COMPATIBILISATION WITHOUT ADDITION OF PREMADE BLOCK OR GRAFT COPOLYMERS OR FUNCTIONALISATION Furgiuele N Khait K Torkelson J M (ACS,Div.of Polymer Chemistry)... 

Guebitz GM, Cavaco-Paulo A (2008) Enzymes go big surface hydrolysis and functionalisation of synthetic polymers. Trends Biotechnol 26 32-38... 

The column (trap) is made of molecular sieves of absorbing materials such as graphite-based carbon black or functionalised organic polymers, fn certain... 

A related series of 5-substituted-2-amino-oxadiazole compounds have also been prepared in a one-pot procedure using a microwave-assisted cyclisation procedure (Scheme 6.26)164. Rapid preparation of the pre-requisite ureas from the mono acyl hydrazines and various isocyanates (or the isothiocyanate) was easily achieved by simple mixing. The resulting products were then cyclo dehydrated by one of the two procedures either by the addition of polymer-supported DMAP and tosyl chloride or alternatively with an immobilised carbodiimide and catalytic sulphonic acid. Purity in most cases was excellent after only filtration through a small plug of silica but an SCX-2 cartridge (sulphonic acid functionalised - catch and release) could be used in the cases where reactions required additional purification. 

In a more recent study, Westman and Lundin described the solid-phase synthesis of aminopropenones and aminopropenoates, respectively30 as intermediates for heterocyclic synthesis. Two different three-step methods for the preparation of heterocycles have been developed. The first method involved formation of a polymer-bound ester from a IV-protected glycine derivative and Merrifield resin (Scheme 7.10a), while the second method employed an interesting approach utilising simple aqueous methy-lamine solution for functionalisation of the solid support (Scheme 7.10b). In this latter approach, a variety of hetero cycles were readily synthesised from the generated polymer-bound benzylamine using a two-step protocol (see Section 5.3.3). 

An interesting and recently published study presented the functionalisation of insoluble polystyrene resin with soluble polyethylenglycol (PEG) (Scheme 7.46) to produce hybrid polymers that combine the advantages of both PEG and polystyrene as polymeric supports52. 

Molecularly imprinted composite membranes have been developed based on the functionalisation of a commercial membrane with an MIP in order to improve the mechanical stability of the imprinted polymer phase, similarly to the preparation of MIP composite beads, discussed in Sect. 2.2.2. 

Polymer-analogous variants reach their limits in the face of insufficient rigidity of the functionalised linear polymers which can lead to undesired coiled structures. These have to re-assume a linear structure, with an attendant loss of entropy, in order to assure reaction of all the dendrons with the functional groups attached to the backbone. The dendrons are mostly added in excess in order to facilitate complete reaction, which in turn necessitates tedious purification of the products. The additional steric hindrance occurring on attachment of larger dendrons if higher generation dendrons are already located in the close... 

Chapters 2 and 3 have already introduced the reader to the general principles of the architecture, synthesis, and functionalisation of dendritic molecules - including hyperbranched and dendronised (linear) polymers (denpols). This chapter will now consider specific molecular scaffolds and syntheses of important types of dendrimers and their individual properties. More specialised and appli-cations-relevant properties of particular dendrimers are compiled in Chapter 8. 

Polymer brushes are polymers tethered to a surface via one end. The connection to the surface can be covalent or non-covalent, and the brushes can be made via grafting to or grafting from the surface. In the past few years, there has been considerable interest in the growth of polymer brushes via surface-initiated polymerisations from (patterned) initiator-functionalised SAMs.62,63 For example, we have recently shown that surface confined Atom Transfer Radical Polymerisations (ATRP) in aqueous solvents leads to rapid and controlled... 

Functionalisation of the polymer backbone through reaction of the hydroxyl groups (esterification and etherification), nucleophilic displacement reactions, oxidation and selective reactions at the terminal reducing ends... 

Related to ionic liquids are substances known as deep eutectic solvents or mixtures. A series of these materials based on choline chloride (HOCH2CH2NMe3Cl) and either zinc chloride or urea have been reported (Abbott et al., 2002 2003). The urea/choline chloride material has many of the advantages of more well-known ionic liquids (e.g. low volatility), but can be sourced from renewable feedstocks, is non-toxic and is readily biodegradable. However, it is not an inert solvent and this has been exploited in the functionalisation of the surface of cellulose fibres in cotton wool (Abbott et al, 2006). Undoubtedly, this could be extended to other cellulose-based materials, biopolymers, synthetic polymers and possibly even small molecules. 

The use of borane-containing monomers clearly presents an effective and general approach in the functionalisation of polyolefins, which has the following advantages stability of the borane moiety to coordination catalysts, solubility of borane compounds in hydrocarbon solvents (such as hexane and toluene) used as the polymerisation medium, and versatility of borane groups, which can be transformed to a remarkable variety of functionalities as well as to free radicals for graft-form polymerisations. The functionalised polymers are very effective interfacial modifiers in improving the adhesion between polyolefin and substrates and the compatibility in polyolefin blends and composites [518],... 

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