Succinoylation of wheat straw hemicelluloses with a low degree of substitution in aqueous systems

The reaction of wheat straw hemicelluloses with succinic anhydride in aqueo us alkaline systems was studied. The products showed a rather low degree of substitution, ranging from 0.017 to 0.21. The effects of reaction times of 0.5-16 h, temperatures of 25-45 degreesC, and molar ratios of succinic anh ydride to anhydroxylose units in hemicelluloses of 1:5-1:1 on the succinoyl ation yield and degree of substitution were examined. With the reaction kep t within a pH range of 8.5-9.0, a temperature range of 25-28 degreesC, a re action duration of 1-2 h, and a 1:1 molar ratio of succinic anhydride to he micelluloses were preferred. The structure of the resulting polymers was de termined with Fourier transform infrared and H-1- and C-13-NMR spectroscopy , which indicated monoester substitution. The thermal stability of the este rified polymer increased with chemical modification. (C) 2002 John Wiley & Sons, Inc. J Appl Polym Sci 83: 757-766, 2002.