高等学校化学学报 ›› 1991, Vol. 12 ›› Issue (8): 1126.

• 论文 • 上一篇    下一篇

黄原胶的数均分子量研究

张俐娜, 黄爱辉, 徐静娟   

  1. 武汉大学化学系, 武汉, 430072
  • 收稿日期:1990-08-16 出版日期:1991-08-24 发布日期:1991-08-24
  • 通讯作者: 张俐娜

A Study on Number Average Molecular Weight of Xanthan

Zhang Li-na, Huang Ai-hui, Xu Jing-juan   

  1. Department of Chemistry, Wuhan University, Wuhan, 430072
  • Received:1990-08-16 Online:1991-08-24 Published:1991-08-24

摘要: 用改良型Bruss膜渗透计测定了黄原胶超声波碎片的6个分级试样的数均分子量Mn及第二维利系数A2,黄原胶在0.1mol/LNaCl水溶液中的Mn值大约是镉乙二胺饱和水溶液(cadoxen)中Mn的2倍,表明它在0.1mol/LNaCl水溶液中为双螺旋链同时共存少量单链分子的双或多股缔合体,而在cadoxen中则变为单无规线团,在cadoxen/水混合液中当cadoxen重量分数Wcad为0.6左右时,黄原胶双螺旋链及缔合分子解开成单股链的过程基本完成。

关键词: 多糖, 黄原胶, 双螺旋构象, 膜渗透压法, 数均分子量

Abstract: The number average molecular weights Mn and the second virial coefficients A2for six fractions of xanthan sonicated fragments were measured by an improved Bruss membrane osmometer according to dynamic and high speed static osmometry in0.1 mol/Laqueous solution of NaCl, cadoxen and water/cadoxen mixtures at 25℃. The ratio Mn(in 0. 1 mol/L NaCl)/Mn(in cadoxen) was equal nearly to 2. It is concluded that the double-stranded helix and a few bi-or perhaps multi-molecular associates of xanthan coexist in 0. 1 mol/Laqueous NaCl, and dissociate into single random coil chains in pure cadoxen. When the weight fraction Wcadof cadoxen in the mixed solvent was about 0. 6, the double helical structure was almost completely broken to single.

Key words: Polysaccharide, Xanthan, Double helix conformation, Membrane osmometry, Number average molecular weight

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