Rayon grafting

The structure of PP-g-polystyrene was studied by wide and narrow angle x-ray diffractometry. The polystyrene component formed discrete amorphous structures, which were identified after chloromethylation [143]. Structure of Rayon-Styrene graft copolymer was characterized by IR, wide angle x-ray, and SEM, grafting occurred mainly in the amorphous regions of rayon [1441. 

An interesting redox system for grafting, containing cumene hydroperoxide and Fe + ions, has been developed by Simionescu et al. U. They grafted acrylonitrile and isoprene to rayon fibers at low temperatures (20 to A0°C) and long reaction times (up to... 

The peracetic initiator has been successfully applied also for grafting onto rayon fibers and cellophane22. The peracetic initiator has been further developed by Hatakeyama2 who combined the peracetic acid with Fe2+ or Fe + ions to a redox system found to be an effective initiator for grafting to pulps and isolated lignin. The reactions... 

The first application of the ferrous ion-hydrogen peroxide initiation for polymerizing vinyl monomers on and into cellulose fibers has been reported by Landeias and Whewell (41) in three successive papers. They are apparently the first who applied the "anchored catalyst technique, which other people have termed "in situ polymerization to cellulose grafting. The authors internally deposited methyl methacrylate, acrylonitrile, styrene, methyl vinyl ketone and methacrylamide in amounts between 10 and 80%. No attempt had been made to determine if actual grafting had occurred. In 1961 Richards (42) studied this question in great detail. Products obtained by polymerization of acrylonitrile and of styrene in viscose rayon were acetylated. Fractionation of... 

In a few cases other redox systems are recommended to initiate grafting to cellulose. Asahi Chemical Industries (62) was granted a patent to graft acrylonitrile to viscose rayon fibers using ferrous sulphate and sodium formaldehyde-sulphoxylate as initiator. 

Kargin, Usmanov, and Aikhodzhaev (64) used a similar technique of ozonization to introduce hydroperoxide groups into cellulose substrates. They observed grafting of styrene to ozonized viscose tire cord even without the presence of any other initiating system imparting improved rubber-adhesion to the rayon tire cord. In a later report, Usmanov, Aikhodzhaev, and Azizov (65) described the grafting of acrylonitrile, methyl methacrylate, methylvinylpyridine, and of vinylacetate onto ozonized cellulose. 

The graft copolymerization of acrylonitrile and of styrene onto regenerated celluloses, such as viscose rayon and cellophane, and onto cellulose acetate has been investigated by Pikler, Suta, and Alfoeldi (68) and by Alfoeldi and Pasteka (69). In both studies the authors used ozonized substrate for initiating the graft copolymerization. 

The selective oxidation of cellulose to dialdehyde by sodium periodate is well known. It has been postulated by Criegee (74) and by Waters (73) that this reaction proceeds by a free radical mechanism. Toda (76) and Morimoto, Okada, Okada, and Nakagawa (77) have concluded that sodium periodate oxidation should initiate graft polymerization. They succeeded in grafting methyl methacrylate and acrylonitrile onto cellulose substrates, such as rayon and paper. A similar procedure is recommended in a patent of Chemische Werke Huels (78) to graft vinyl monomers onto cotton, polyethylene oxide, copolymers of vinyl chloride-vinyl acetate, and others. 

Also other oxidants have been used successfully to initiate graft copolymerization onto cellulose substrates. Toyo Rayon (79) achieved grafting by pretreatment of viscose rayon fibers with potassium permanganate-sulfuric acid and contacting it subsequently with acrylonitrile. Methyl methacrylate is being grafted to rayon when heated together with potassium bromate, as claimed by Asahi Chemical Industry... 

Company (80). Rayon pretreated with hydrogen peroxide initiated grafting of styrene from an emulsion as reported by Toyo Spinning Company (81). 

Araki et al. (117) have described a so-called dry-state grafting procedure in which the cellulose is boiled with water and then the water is replaced by various alcohols, also by boiling. The cellulose was then dried and grafted with styrene using both mutual and pre-irradiation methods. The treatment was effective with cotton but only to a small extent with rayon fibers. The order of effectiveness of the solvents used was butanol as the most effective and methanol, water, higher alcohols and ketones as considerably less effective. This is a different order from... 

Armstrong, and Rutherford have reported extensive studies on the vapor phase grafting of vinyl monomers to cellulosic fibers both mutual and pre-irradiation methods have been used (97, 120). Again, water or another swelling agent was found to be necessary for effective grafting to rayon and cotton for all the monomers studied. In the case of cellulose acetate water was helpful but not necessary except for styrene. Acetic acid and methanol vapors were also found to be effective promotors of vapor phase grafting to cotton and cellulose acetate fibers. 

The production of aldehyde groups through periodate oxidation and subsequent formation of oxime groups is being used as a basis for an anionic initiation of grafting with titanium chloride as catalyst according to a process claimed by Asahi Chemical Industries Company (135). With this method styrene was grafted onto viscose rayon. Also bi- and tri-valent vanadium salts can be used as initiators. 

Strength properties of rayon-polystyrene graft copolymers (single fiber tests) (108)... 

Yoshitake, I., and S. Obuchi The change in fine structure of rayon by grafting of methyl acrylate. J. Soc. Text, and Cell. Ind. (Japan) 19, 540... 

Akiyama, Y. (assignor to Asahi Chemical Industry Co. Ltd.) Rayon-methyl methacrylate graft copolymer. Japan 7877/63 (June 3, 1963). 

Suzuki, I., and S. Ogawa Effect of addition of cations on the simultaneous grafting of styrene to rayon by gamma-irradiation. J. Appl. Polymer Sci. 7, 2067 <1963). 

Percent Extractable Homopolymer, Molecular Weights and Average Number of Cellulose Molecules per Grafted Cellulose. Xanthate Grafting of Various Monomers to Rayon (Taken from Krassig) Ref. 18. 

Molecular Weights Styrene to Rayon. Huang) Ref. 25. and Radiation Yields Mutual Method with (G values) Preswelling. for Grafting (Taken from... 

Effect of the Addition of Carbon Tetrachloride to the Styrene Grafting Solution, Preirradiation Method to Rayon Fibers. (Adapted from Min and Inagaki) Ref. 13. 

---