Vinyl monomers grafted

If polyvinyl alcohol is used as the reducing agent and the oxidation is conducted in the presence of vinyl monomer, grafting occurs. This method of grafting yields substantially pure graft copolymers since the free radicals are formed exclusively on the polymer backbone. 

Flexible polyurethane foam pre-irradiated with ionizing radiation in the presence of air can be readily grafted with vinyl monomers. Relatively low radiation doses (3 to 10 megarads) are required to graft various polar vinyl monomers. Grafting of as little as 2% by weight of acrylamide, methacrylamide, or acrylic acid converts the normally hydro-phobic polyurethane foam into a water-wettable sjjonge. 

However, since free radicals generally lack selectivity in attacking substrates or vinyl monomers, grafting efficiencies lower than 100% are to be expected. 

Grafting of methyl methacrylate on starch occurs in an aqueous, saturated starch solution at 85 °C in the presence of carbon tetrachloride or copper(II) ions,2808,2809 and the grafting efficiency could be as high as 72%. At a low concentrations of the vinyl compound, the reaction rate was proportional to its concentration. The reaction rate became independent of concentration at higher concentrations of the vinyl monomer. Grafting in the presence of 0.1M nitric acid and ammonium selenate was also reported.2810... 

Acrylic acid or methacrylic acid-starch graft copolymers were proposed as floc-culants for bauxites,2714,3095 agents for sizing cotton,3096-3098 tanning materials,3099 paper additives,3100 and also for sanitary napkins, diapers, tampons, and sick-bed sheets.3101-3104 Particular attention was devoted to the use of vinyl monomer grafted onto crosslinked starch.3105 Other applications include antiflammatory... 

Another potentially important development in the free-radical polymerization area is the nitrile barrier resins. These products generally are graft polymers containing a glassy phase comprised of 80% acrylonitrile and 20% styrene or other vinyl monomer grafted onto a rubber substrate. The commercialization of these materials has been interrupted by an adverse ruling by the Food and Drug Administration (FDA) in connection with extraction of traces of acrylonitrile in food-related applications. The amounts involved are very small. A new attitude under development in the FDA may lead to the eventual clearance of these materials. 

S. H. Feairheller, A. H. Korn, E. H. Harris, Jr., E. M. Filachione, and M. M. Taylor, Graft Polymerization of Vinyl Monomers onto Chrome-Tanned Hides and Skins, U.S. Pat. 3,843,320 (1974). Semi-I IPNs of vinyl monomers grafted onto leather. Emulsion process for transporting the monomer into the leather. Mechanical properties. 

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