Surface-active agents, grafting monomer

Grafting of Monomer to Surface-Active Agents. A recent patent claims the preparation of a F/T stable poly(vinylacetate-vinylbenzoate) copolymer emulsion in the presence of a graft polymer of vinylacetate on a polyalkylene glycol (21). 

The membranes were prepared by volume grafting of acrylic acid onto polypropylene activated by soft oxidation of the polymer in the presence of tert-butylhydroperoxide as the initiator and sodium dodecylsulphate as the surface active agent. During the preparation, samples of preactivated polypropylene film were immersed in aqueous solution of acrylic acid of 1,84 mol/dm concentration for periods of time ranging from 4 up to 14 hrs. The monomer penetrating the film by sorption was polymerized within the film at 358 K. 

Free-radical method usually requires a surface activation by a direct attachment of initiator molecules or by the introduction of surface active sites (i.e., vinyl groups in surface graft polymerization of vinyl monomers). In particular, organosilane coupling agents (i.e., chloro- and alkoxysilanes) are commonly employed to introduce active sites onto inorganic oxide surfaces. 

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