Mechanochemically initiated copolymerization

Mechanochemically Initiated Copolymerization Reactions in Cotton Cellulose... 

Mechanochemically Initiated Graft Copolymerization. According to the ESR study, it is clear that mechanoradicals were generated in cellulose either by means of mechanical cutting or ball milling. These mechanoradicals may be utilized as reaction sites for the initiation of vinyl polymerization which would result in graft copolymerization of cellulose. Based on this principle, the ability of cellulose mechanoradicals to initiate copol3nnerization was pursued. 

Experiments were also performed with the aim of polymerizing a mixture of two monomers (69). The reaction rate and the composition of the graft copolymer conform to the rules of mechanochemical synthesis and radical copolymerization. If the two monomers have almost equal reactivities, the composition of the copolymer is approximately that of the initial monomer mixture (Fig. 20). The... 

Experiments were also performed with the aim of polymerizing a mixture of two monomers [88]. The reaction rate and the composition of the graft copolymer conform to the rules of mechanochemical synthesis and radical copolymerization. If the two monomers have almost equal reactivities, the composition of the copolymer is approximately that of the initial monomer mixture (Fig. 5.20). The reaction rate is also intermediate between those of the separate monomers. If the two mechanically activated monomers have different reactivities, the two monomers largely polymerize separately. The reaction rate depends on the polymer properties for the monomer that polymerizes first. As an example, in the system chloroprene-methyl methacrylate [88], the more active chloroprene polymerizes at first the reaction rate is low as polychloroprene is a flexible chain and the second monomer behaves as an inert solvent, reducing the viscosity. The reaction rate increases in the second part of the reaction when an appreciable amount of poly-(methyl methacrylate) is produced (see Fig. 5.21). Two monomers added... 

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