Grafting Onto Technique

In the grafting onto technique, the macromolecular branches are linked to the main chain by specific reaction between their a or co end group and reactive functional groups in the backbone. 

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The synthesis of graft copolymers by grafting from and grafting onto techniques are reported in Table 4. 

SCHEME 13.6 Synthesis of graft copolymers by photoinduced grafting onto technique. 

To the best of our knowledge, no literature work has been reported describing the use of photoinduced grafting onto technique, which seems almost impossible to achieve. Grafting Onto is best defined as the attachment of end-functional polymeric chains, namely, telechelics, onto specific sites on polymer backbones or surfaces via a chemical reaction (Scheme 13.6). 

Using the grafting onto technique Munir and Goethals bound polyTBA to silica 156). Two routes were used the first, in which silica was reacted with 3-amino-propyl triethoxysilane, followed by reaction with living polyTBA, and the second one, in which polyTBA was reacted with 3-aminopropyl triethoxysilane, followed by reaction with silica ... 

The divergent grafting-from method suffers from a significant drawback in terms of structural characterization. In the grafting-onto techniques, a sample of the side chains can be removed for analysis before the grafting... 

The grafting onto technique involves the use of a backbone polymer with randomly distributed functionalities along the chain. The branches with chain-end functional groups are synthesized and characterized separately. The coupling of branches to the backbone leads to the formation of the graft copolymer. In most of the cases of PLL-based graft copolymers the polypeptide was used as a backbone and its E-NH2 side groups were used for... 

The convergent approach involving CLP and grafting-onto techniques has heen exploited to prepare dendrigrafts and dendrimer-Hke polymers [2, 15, 35, 54]. One advantage of the convergent strategy is that Hnear chains can he sampled out and indej)endently characterized, while one drawback is the need to use an excess of hnear chains to obtain the expected functionahty. 

Figure4 Grafting onto technique after backbone hydrosilylation. Reproduced from Xenidou, M. Hadjichristidis, N. Macromolecules31,...

An alternative (and perhaps more efficient) polymeric snrfactant is the amphipathic graft copolymer consisting of a polymeric backbone B (polystyrene or polymethylmethacrylate) and several A chains (teeth) snch as polyethylene oxide [4], This graft copolymer is sometimes referred to as a comb stabilizer. This copolymer is nsnally prepared by grafting a macromonomer such methoxy polyethylene oxide methacrylate with polymethylmethacrylate. The grafting onto technique has also been nsed to synthesize polystyrene-polyethylene oxide graft copolymers. 

An example of the grafting onto technique is the synthesis of polymethylmethacrylate (PMMA)-graft PEO copolymers. A potassium alkoxide of PEO is grafted onto PMMA by the attack of the alkoxide on the carbonyl group of PMMA with the elimination of the methoxide ion. Fractionation of the crude graft copolymer indicated that the grafting reaction is random with one PEO chain per 10-170 methylmethacrylate units. 

In this paper we report the preliminary results obtained on applying the "grafting onto" technique of anionic graft pol)nnerization to the synthesis of... 

Ckinventional free-radical polymerization, either by so-called graffing-ffom or grafting-onto techniques are the oldest and were the most widely used procedures for the synthesis of graft copolymers because they are very simple [2 ]. In fact, graft copolymers can easily be obtained by polymerization of a monomer A in presence of a preformed polymer B acting, either as a chain-transfer agent or as a macroinitiator. However, these procedures usually... 

Grafting onto techniques in which polymer-segments fitted at one end with a reactive function are reacted with antagonist functions distributed either randomly or regularly on a polymer backbone. 

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