INFLUENCE OF ACETYL AND PYRUVATE CONTENTS ON RHEOLOGICAL PROPERTIES OF XANTHAN IN DILUTE-SOLUTION
INFLUENCE OF ACETYL AND PYRUVATE CONTENTS ON RHEOLOGICAL PROPERTIES OF XANTHAN IN DILUTE-SOLUTION
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DOI：
10.1016/0141-8130(87)90068-7
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发表时间：
1987-10-01
影响因子：
8.2
通讯作者：
RINAUDO, M
中科院分区：
文献类型：
--
作者：
CALLET, F;MILAS, M;RINAUDO, M
本文研究了乙酰基和丙酮酸基对黄原胶在稀溶液中的流变性能的影响。为此，以同一原始样品为原料，通过化学水解制备了一系列黄原原衍生物，即无乙酰、无丙酮酸、无乙酰和无丙酮酸黄原原。通过测量旋光度随温度的变化，跟踪了四种样品（天然黄原胶和改性黄原胶）的构象转变。由此得到的中点转变（Tm）值表明，乙酰基对黄原胶的有序形态有稳定作用，而丙酮酸基则相反。经过超声波部分解聚后，研究了四种样品的粘度随聚合物浓度（低于重叠浓度C*）和分子量的函数关系。得到了[.eta]的独特曲线。]相对于Mw，比粘度相对于重叠参数C[.eta]。]。结果表明，乙酰基和丙酮酸含量对黄原胶稀溶液粘度和一定分子量下黄原胶固有粘度均无影响。
In this paper, we investigate the role of acetyl and pyruvate groups on rheological properties of xanthan in dilute solutions. For this purpose, a series of xanthan derivatives were prepared by chemical hydrolysis from the same original sample, i.e. acetyl-free, pyruvate-free, acetyl and pyruvate-free xanthans. Conformational transitions of the four samples (native and modified xanthans) were followed by measuring optical rotation as a function of temperature. Values of midpoint transition (Tm) thus obtained indicate that acetyl groups have a stabilizing effect on the ordered form of xanthan whereas pyruvate groups have an opposite effect. After partial depolymerization by sonication, viscosities of the four samples were studied as a function of polymer concentration (below overlap concentration C*) and molecular weight. Unique curves were obtained for [.eta.] versus Mw and specific visocity versus the overlap parameter C[.eta.] for the four samples. This result shows that acetyl and pyruvate contents have no influence either on xanthan dilute solution viscosity or on its intrinsic viscosity at a given molecular weight.