Ceric ammonium nitrate copolymers

Both starch-g-PAN and starch-g-polyacrylamide were prepared by cobalt-60 initiation, since acrylamide does not graft efficiently in the presence of ceric ammonium nitrate (16). Both graft copolymers were irradiated with ultrasound to give totally soluble products the ultrasonic treatment of starch-g-PAN was carried out in DMSO, while that of starch-g-polyacrylamide was run in water. 

Film Formation. Starch-g-PAN samples used for this study were prepared as described above, except that the small amounts of PAN homopolymer were not removed by DMF extraction. For the graft polymerization with gelatinized starch, the starch-water slurry was heated for 30 min at 85°C before reaction at room temperature with acrylonitrile and ceric ammonium nitrate. Saponifications in these experiments were carried out by stirring. 55 g of graft copolymer with 450 ml of 0.711 sodium hydroxide solution in a sigma mixer for 2 hr at 90-100°C. 

Another method of graft copolymer synthesis is a combination of microwave-based and conventional synthesis, i.e. using both microwave radiation as well as a chemical free radical initiator (e.g. ceric ammonium nitrate) together. This process is referred to as microwave assisted synthesis [47]. Although it yields a higher percentage grafting than the microwave initiated synthesis, the rehability of the synthesis process is low. 

Synthesis of the Graft Copolymer by Conventional Method (Using Ceric Ammonium Nitrate as a Free Radical Initiator)... 

This oxidative cleavage of the C-2-C-3 bond can also be performed by using ceric ammonium nitrate (CAN), which produces an aldehyde group and a radical function on a carbon atom bearing a hydroxyl group. The resulting compound can then be polymerized with acrylonitrile to form cellulose-polyacrylonitrile graft copolymers (Fig. 31). 

ERB Erbil, C., Gokcoren, A.T., and Polat, Y.A., A-isopropylacrylamide-acrylamide copolymers irtitiatedby ceric ammonium nitrate in water, Polym. Lnt, 56, 547, 2007. 

Chitosan - g - maleic anhydride - g -(acrylonitrile) copol5mier was prepared via free radical polymerization using ceric ammonium nitrate as the initiator. This graft copolymer was used as an adsorbent in dye effluent treatment [73],... 

Generation of radicals by redox reactions has also been applied for synthesizing block copolymers. As was mentioned in Section II. D. (see Scheme 23), Ce(IV) is able to form radical sites in hydroxyl-terminated compounds. Thus, Erim et al. [116] produced a hydroxyl-terminated poly(acrylamid) by thermal polymerization using 4,4-azobis(4-cyano pentanol). The polymer formed was in a second step treated with ceric (IV) ammonium nitrate, hence generating oxygen centered radicals capable of starting a second free radical polymeriza-... 

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