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Mechanochemical Techniques for Formation of Block Copolymers

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  643

2026-03-01

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Mechanochemical Techniques for Formation of Block Copolymers

 These techniques rely upon high shear to cause bond scissions. Ruptured bonds result in formations of free radical and ionic species [413]. When this application of shear is done in the presence of monomers, block copolymers can form. This approach is exploited fairly extensively. Such cleavages of macromolecules can take place during cold mastication, milling, and extrusion of the polymers in the visco-elastic state. Both homolytic and heterolytic scissions are possible. The first one yields free radical and the second one ionic species. Heterolytic scissions require more energy, but should not be written off as completely unlikely [413]. Early work was done with natural rubber [413]. It swells when exposed to many monomers and forms a visco-elastic mass. When this swollen mass is subjected to shear and mechanical scission, the resultant radicals initiate polymerizations. The mastication reaction was shown to be accompanied by formation of homopolymers [413]. Later the technique was applied to many different polymers with many different monomers [414].