Copolymers, graft macromonomer synthesis method

Inifer type reactions have been applied to a large number of cationic synthesis, yielding functional polymers 70 72), block copolymers 73), graft copolymers, and even star-shaped polymers73). As far as macromonomer synthesis is concerned three different methods have been used which are described below ... 

Table 4 summarizes the data reported on the synthesis of graft copolymers through macromonomers prepared by polycondensation methods. 

The reaction scheme of the synthesis of a graft copolymer by macromonomer method is illustrated in Scheme 1. 

Scheme 1. Synthesis of Graft Copolymer by Macromonomer Method...

In the first part of this review we shall consider the various pathways that have been used (or attempted) to synthesize macromolecular monomers. We shall critically discuss the efficiency of the methods that have been proposed, together with the procedures used for the characterization of the species obtained. In the second part we shall describe the various attempts to homopolymerize macromonomers and to use them in copolymerization reactions to obtain graft copolymers. We shall include some potential applications of macromonomers as intermediates to the synthesis of new polymeric materials that have been proposed. 

The polymers prepared by condensation techniques have broad molecular weight distributions but the method is applicable to monomers which cannot be polymerized otherwise. Therefore the synthesis of macromonomers and subsequently graft copolymers with polycondensation methods present special interest. 

Figure 13 Synthesis of graft copolymers by the macromonomer ( grafting through ) method.

Three general methods have been developed for the synthesis of randomly branched graft copolymers (1) the grafting onto , (2) the grafting from , and (3) the macromonomer method (or grafting through method) (8) (Fig. 2). 

The most commonly used method for the synthesis of graft copolymers is the macromonomer method. Macromonomers are oligomeric or polymeric chains bearing a polymerizable end group. Macromonomers having two polymerizable end groups have also been reported (8). Copolymerization of preformed macromonomers with another monomer yields graft copolymers. 

The macromonomer method is probably the most promising development at present concerning the synthesis of well-defined graft copolymers. The developments in this field up to 1999 have been reviewed by Ito and Kawaguchi [181]. Any macromonomer having a head group that is copolymerizable with styrene can be utilized for this purpose. 

Macromonomer method Macromonomers are conveniently used for the graft copolymer synthesis. A macromonomer of PEG chain having an oxazoline polymerizable group was prepared and used for a graft copolymer synthesis (Scheme 23). ... 

Scheme 2 Synthesis of PLA-graft copolymers via two methods (/) macromonomer approach and (IF) copolymer approach. See text for description of reactions...

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