Robert C. Burr

Copolymers of Starch and Polyacrylonitrile. Influence of Granule Swelling on Copolymer Composition under Various Reaction Conditions

Abstract Molecular weights and grafting frequencies of graft copolymers prepared with ferrous ammonium sulfate-hydrogen peroxide initiation showed a dependence on granule swelling similar to that found with ceric ammonium nitrate (increased swelling of starch granules decreased the number of grafted polyacrylonitrile chains and increased their average molecular weight). As with unswollen starch, the composition of the copolymer prepared from swollen starch was not influenced by granule size. Molecular weights of polyacrylonitrile branches grafted to swollen and unswollen starch were independent of reaction time; however, grafting frequencies with swollen and unswollen starch tended to converge toward a common value with increased reaction time and increased dilution. Data suggest that the influence of granule swelling on copolymer composition is due to a faster termination rate for growing polyacrylonitrile chains in unswollen starch.

Copolymers of Wheat Starch and Polyacrylonitrile. Effect of Aqueous-Organic Solvent Systems on Copolymer Composition

Abstract Starch-polyacrylonitrile graft copolymers prepared in a number of aqueous-organic solvent systems with ceric ammonium nitrate as the initiator had more grafted chains than those prepared in water alone, and these were of lower molecular weight. Substitution of methanol for 80% of the water produced grafted chains with a molecular weight of 15,700 and a grafting frequency of 253 anhydroglucose units per graft. The influence of catalyst concentration, increased reaction temperature, and sodium sulfate on the composition of the copolymer were investigated for the methanol-water system.

Oil Absorbency of Graft Copolymers from Softwood Pulp

Considerable research has been devoted to developing oil absorbents for clean-up of oil spills and removal of emulsified oil from waste water. Agricultural products and residues, such as kapok fiber,1 cotton,2,3 rice hulls,4 corncob meal,5 bagasse fibers,6 and peat moss7 have been used for this application, and these materials have the advantage of being inexpensive and readily available. Moreover, cellulosic products exist in fibrous form and can be easily formed into mats, pads, and nonwoven sheets. Mats and column packings for oil removal have also been prepared by mixing cellulosic fibers with synthetic fibers, e.g., polyethylene8 or polypropylene-polyethylene-nylon blend.9 Cellulosics have also been mixed with inorganic materials, such as clay,10 magnesium hydroxide, and alumina11 to give oil-absorbent compositions.