Mechanochemically initiated

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. 

Mechanochemical initiation can be of some importance in the industrial production of block and graft copolymers. The remainder of the these methods of radical generation are not much used in technical applications. 

Falenczyk C, Polloth B, Hilgers P, KOnig B. Mechanochemically initiated Achmatowicz rearrangement. Synth Commun 2014 45 348-54. 

There is also evidence that mechanochemical processes occur during the ageing of rubber vulcanizates (see Kuz minskii, 1966). The observation by Brodskii et al. (1960) that the abrasion rate of natural rubber is greater in air than in nitrogen and that antioxidants have a significant effect on wear resistance can be explained in terms of a mechanochemically initiated autoxidation reaction. It is also the belief of this writer that anomalous results on the abrasion resistance of natural rubber vulcanizates (Southern and Thomas, 1977) are explicable in terms of inhibition of crystallization by a mechanochemically initiated oxidation reaction. 

The above approach of mechanochemically initiated addition of reactive antioxidants on different polymers, such as rubbers and unsaturated thermoplastics such as ABS is illustrated here for thiol-containing antioxidants. For example, using thiol compounds (37) and (38) as the reactive antioxidants, Kharasch-type addition of the thiol function to the polymer double bond takes place during melt processing to give bound antioxidant adduct (see reaction 7) the polymer becomes much more substantive under aggressive environments. 

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