New method for graft polymerization of vinyl monomers in wool fibers

Abstract

synopsisWhen a small amount of persulfate is dissolved in a relatively concentrated aqueous solution of bromide salts, especially LiBr, liberation of Brz occurs to some extent. This system waa utilized for the graft copolymerization of various acrylatea in wool fibers using diethylene glycol monobutylether as monomer-solubilizer. The grafting waa fairly well performed a t a relatively low temperature (1MO"C.) and without homopolymerization while liberating Br2. This new graft copolymerization has been attributed to the concerted action of the fiber-swelling power of bromide salta, the following redox system, and the mild bromination of some monomers by which the grafting will proceed without homopolymerization.It is known that the bromides of alkali metals or ammonium are well absorbed by protein materials such as wool, silk, or gelatin accompanying its hydration, swelling, or contraction, more or less according to the lyotropic series of cations (Li+ > Na+ > K+ for wool or silk, Li+ > NH4+ > Na+ > K+ for When a small amount of persulfate, in the form of K2SzOs or (NH4)2S20s, is dissolved in relatively concentrated aqueous solutions of these bromides, the liberation of Br2 occurs to some extent. The mechanism of this reaction involves the following redox system:The facility of Br2 liberation was observed to be in the order K+ > NHI+ 2 Na+ > Li+ and decreased with increasing the degree of hydration of bromide.Thus, we attempted to utilize the fiber-swelling action of these bromides and the redox system formed between Br-and S2OS-for the graft copolymerization of vinyl monomers in wool fibers. In order to solubilize vinyl monomers, especially water-insoluble monomers, in the aqueous solutions 3465

Grafting onto cellulose. VIII. Graft copolymerization of poly(ethylacrylate) onto cellulose by use of redox initiators. Comparison of initiator reactivities

“…Excess of KPS also is expected to decrease percent grafting since some of the OH is wasted in side reactions with KPS. (12) *OOSO, + Fe3+ -0, + SO, + Fe2+ (13) It is apparent from the above considerations that the molar ratio of [KPS]/ [FAS] will influence percent grafting. A similar explanation for the dependence of percent grafting on the molar ratio of [HzOz]/[FAS] is also valid with Fenton's reagent.…”

Grafting onto wool. III. Graft copolymerization of poly(vinyl acetate) by use of fenton's reagent as initiator

“…In analogy with BPO-initiated grafting, the following plausible mechanism [eqs. (1)(2)(3)(4)(5)(6)] is suggested for Fenton's reagent-initiated grafting of poly(viny1 acetate) onto wool, where WH denotes the polymeric backbone, wool.…”

An investigation into the effects of graft polymerisation of vinyl monomers to wool

“…Polymer can, on occasion, form in solution and precipitate onto the fibre surface. This homopolymer is generally undesirable as it is not covalently bound and is therefore susceptible to later removal [9]. Internal grafting can have far-reaching effects on the fibre's properties, although it is generally less effective than deposition methods in conferring shrinkresistance.…”