Graft copolymerization of cellulose

Photoinduced graft copolymerization of cellulose derivatives especially containing carbonyl groups in the absence of a photosensitizer, has been investigated. Grafting of methyl methacrylate onto dialdehyde and dicarboxyl celluloses proceeded more easily than onto monocarboxyl cellulose. The grafting efficiency of the former two samples attained to 95-100%. 

Influence of the cellulose structure and of the chemical structure of the grafted polymer on the kinetics of graft copolymerization of cellulose, on the composition, and the structure of the cellulose products. 

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. 

Samal RK, Sahoo PK, Samantaray HS (1986) Graft copolymerization of cellulose, cellulose derivatives, and lignocellulose. J Macromol Sci Rev Macromol Chem Phys 26 81-141... 

The hydrogen abstraction from —SH groups is faster than from —OH groups. Hebeish et al. [9] and Misra et al. [10,11] reported the chain-transfer method of initiation of graft copolymerization onto cellulosic substrates with azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO) as initiators. 

Graft copolymerization of acrylonitrile with various vinyl comonomers such as methyl acrylate, ethyl acrylate, vinyl acetate, and styrene onto cellulose derivatives using ceric ion was studied [24]. The results showed that... 

In aqueous solutions the persulphate ion is known as a strong oxidizing agent, either alone or with activators. Thus, it has been extensively used as the initiator of vinyl polymerization [43-47]. However, only later, Kulkarni et al. [48] reported the graft copolymerization of AN onto cellulose using the Na2S203/K2S20s redox system. 

Recently, Li et al. [30], Yu et al. [31] reinvestigated the mechanism of graft copolymerization of vinyl monomers onto carbohydrates such as starch and cellulose initiated by the Ce(IV) ion with some new results as mentioned in Section II. Furthermore, they investigated the mechanism of model graft copolymerization of vinyl monomers onto chitosan [51]. They chose the compounds containing adjacent hydroxyl-amine structures, such as D-glucosamine, /mn5-2-amino-cyclohexanol, 2-... 

Peracetic acid, formed in situ from acetic acid and hydrogen peroxide in acid aqueous solution, was found to initiate graft copolymerization of vinyl monomers, e.g. methyl methacrylate and 4-vinyl pyridine, onto wood and cellulosic fibers at a good rate (1-3 h time) at 60°C2. The initiati on reaction is not specific for grafting and considerable amounts of homopolymer is formed. 

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. 

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... 

Sakurada, I., T. Okasa, Hatakeyama, and F. Kimura. Radiation-induced graft copolymerization onto cellulose and polyvinyl alcohol fibers with binary mixtures of comonomers. J. Polymer Sci. C 4, 1233 (1964). 

Kobayashi, Y. Gamma-ray induced graft copolymerization of styrene onto cellulose and some chemical properties of the grafted polymer. J. Polymer Sci. 51, 359 (1961). 

Graft Copolymerization of Vinyl Monomers onto Cellulosic Fibers... 

The results of the graft copolymerization on cellulose in various conditions are shown as a function of the irradiation time, initiator concentration, monomer concentration, presence of additive. 

Graft Copolymerization. Graft copolymers of cellulose and cellulose derivatives were prepared in a quartz reactor containing 0.5 g oven dried sample, 10 ml monomer and 100 ml water at 45°C. The grafting mixtures or solutions were photo-irradiated with the ultraviolet light of X > 254 nm and X >... 

Figure 6. Effect of grafting time on the graft copolymerization of methyl methacrylate onto cellulose nitrate with ceric ammonium nitrate as initiator. (Reprinted, with permission, from Ref. 19. Copyright 1979, Wiley.)...

Figure 10. Effect of initiator concentration on the graft copolymerization of methyl methacrylate onto cellulose nitrate initiated by a, benzoyl peroxide and b, azobisisobutyronitrile. Key O, grafting efficiency 9, percent grafting.

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