Vernetzung von amylose mit Epichlorhydrin, 2. Untersuchung der Vernetzungsprodukte nach dem Gelpunkt
✍ Scribed by Pfannemüller, Beate ;Sperlich, Marianne
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1978
- Weight
- 770 KB
- Volume
- 179
- Category
- Article
- ISSN
- 0025-116X
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✦ Synopsis
Abstract
A series of amylose gels prepared by reaction of amylose solutions in 1 M aqueous NaOH with 1‐chloro‐2,3‐epoxypropane (epichlorohydrin) at different concentrations were characterized by several methods: (a) The density of cross‐links was estimated by equilibrium swelling of the gels in water at room temperature. The molecular weight of the segments between the cross‐links (M~c~) derived from the Flory equation decreased exponentially with the epichlorohydrin concentration used for gelation. The results obtained for weakly cross‐linked gels are in the same order as the values determined previously by analytical methods. (b) Further differentiation of the gels and the corresponding sol fractions was achieved by enzymes specific for amylose. The size of the fragments resistent to α‐amylase was found to increase linearly with epichlorohydrin concentration. Only minor attack by the exo‐enzyme β‐amylase was found, indicating lack of longer unsubstituted pendant branches. The presence of some short branches is deduced from their priming activity in phosphorolytic synthesis. The grafted amylose chains are located solely at the surface of the gels. The weakly cross‐linked gels give characteristic colours with iodine indicating slightly longer free amylose segments in the gel than in the corresponding sol. The nature of iodine binding by cross‐linked amylose chains is discussed.