کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1378809 | 982010 | 2009 | 9 صفحه PDF | دانلود رایگان |
Poly-(ε)-caprolactone grafted corn starch co-polymers were synthesized using a hydrophobised silylated starch precursor. The silylation reaction was performed using hexamethyl disilazane (HMDS) as the reagent in DMSO at 70 °C. Silylated starch with a degree of substitution (DS) between 0.45 and 0.7 was obtained. ε-Caprolactone is grafted to silylated starch by a ring-opening polymerisation catalysed by Al(OiPr)3 in THF at 50 °C. The grafting efficiency varies between 28% and 58%, the remainder being homopolymers of ε-caprolactone. The DS of the polycaprolactone graft is between 0.21 and 0.72. The poly-(ε)-caprolactone side chains consist of 40–55 monomer units and is a function of the reagent intakes. Experiments with native starch under similar conditions do not result in the desired poly-(ε)-caprolactone grafted corn starch co-polymers and unreacted starch was recovered after work-up. Removal of the silyl groups of the poly-(ε)-caprolactone grafted starch co-polymers is possible using a mild acid treatment with diluted hydrochloric acid in THF at room temperature.
Journal: Carbohydrate Polymers - Volume 77, Issue 2, 10 June 2009, Pages 267–275