Acrylonitrile grafting

Acrylonitrile has been grafted onto many polymeric systems. In particular, acrylonitrile grafting has been used to impart hydrophilic behavior to starch (143—145) and polymer fibers (146). Exceptional water absorption capabiUty results from the grafting of acrylonitrile to starch, and the use of 2-acrylamido-2-methylpropanesulfonic acid [15214-89-8] along with acrylonitrile for grafting results in copolymers that can absorb over 5000 times their weight of deionized water (147). 

Etherification and esterification of hydroxyl groups produce derivatives, some of which are produced commercially. Derivatives may also be obtained by graft polymerization wherein free radicals, initiated on the starch backbone by ceric ion or irradiation, react with monomers such as vinyl or acrylyl derivatives. A number of such copolymers have been prepared and evaluated in extmsion processing (49). A starch—acrylonitrile graft copolymer has been patented (50) which rapidly absorbs many hundred times its weight in water and has potential appHcations in disposable diapers and medical suppHes. 

Not only ate ABS polymers useful engineering plastics, but some of the high mbber compositions are excellent impact modifiers for poly(vinyl chloride) (PVC). Styrene—acrylonitrile-grafted butadiene mbbers have been used as modifiers for PVC since 1957 (87). 

E4 polystyrene-Z)/ocA -[l,4-polybutadiene-grq/Z -poly(styrene-co-acrylonitrile)] (copolymer from styrene and acrylonitrile grafted to a 1,4-polybutadiene-polystyrene two-block copolymer at unspecified sites of some of the but-2-ene-... 

Oxygen free irradiation of solid polymers was also carried out in the absence of monomer in this case free radicals with relatively long life time are produced which are able to initiate the polymerization of a second monomer (56,113). Several irradiated polymers have been used as initiators of polymerization, and, evidently, if the polymerization of the second monomer is initiated only by these frozen-in radicals, the product will undoubtedly be hundred per cent grafted. Bevington using 14C-acrylonitrile was able to estimate the amount of acrylonitrile grafted on preirradiated polystyrene, polyacrylonitrile, polyethylene terephtha-Iate and nylon yams (36,37). 

Separation of acetic acid-water mixtures through acrylonitrile grafted poly(vinyl alcohol) membranes by pervaporation... 

Acrylonitrile grafted poly(vinyl alcohol) membranes were found to be capable of permeating water in preference to acetic acid from aqueous acetic acid mixtures. The permeation rate of water increases whereas permeation rate of acetic acid decreases as the water content of the feed increases. It was also determined that increase in temperature increased the permeation rate without affecting the separation factor much. As the downstream pressure increased permeation rate increased whereas separation factor decreased and from the PSI values of the membranes it could be said that especially at high acetic acid concentrations membranes behaved more separable. 

Ligno Styrene, acrylonitrile Grafting of styrene in methanolic solution [190,... 

Acrylonitrile graft polymerizes readily with either granular or pasted starch to yield starch-g-polyacrylonitrile (PAN), and reactions are generally carried out in water with ceric ammonium nitrate as the initiating system CL). Reaction of starch-g-PAN with alkali at elevated temperatures converts the nitrile substituents of PAN to a mixture of carboxamide... 

The maximum grafting percentage for acrylonitrile-grafted bamboo was found to fall in the range 40-50. The maximum values are quite comparable with the data reported by Hebeish et al. (6) for grafted cotton. 

Figure 17. Styrene and acrylonitrile grafted onto polybutadiene vs. monomer converted, doubly precipitated...

Acrylonitrile graft spray 2% K2S208, acrylonitrile vapor... 

Table 9. Styrene-acrylonitrile grafting onto isobutene copolymers ... 

Additional information on starch graft polymers can be found in reports by Watanabe and Nakano,2701 Fanta,3029 Lindsay,3030 (this reference concerned only starch-acrylonitrile graft polymers), Stannett et a/.,3031 Tokuda,3032 Ransby and Persson,3033 Yoon Kee Jong,3034 Chinnaswamy and Hanna,3035 Zhang Yousong and Li Guangfeng,3036 Doane,3037 and Buchholz.3038... 

Critchfield et al. (109) have also reported the use of acrylonitrile-styrene graft polyols in urethane polymers. The presence of styrene prevents the tendency toward yellowing of the acrylonitrile graft copolymers, which is due to cyclization of the polyacrylonitrile chains at elevated temperatures. Similar types of graft polyols have been reported elsewhere (110). 

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