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Phase transition of thermosensitive amphiphilic cellulose esters bearing olig(oxyethylene)s (2000)

Zhou, Qui ; Zhang, Lina ; Minoda, Masahiko ; [et al.]

Springer

Polymer bulletin 45 (2000), S. 381-388

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ISSN: 1436-2449

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Notes: Summary A series of cellulose esters bearing olig(oxyethylene)s with different degree of substitution (DS) and different length of the oxyethylene chain were synthesized by a homogeneous reaction of cellulose with corresponding monofunctional acid chloride in a 10% LiCl-dimethyl acetoamide (DMAc) solution. The effect of total DS value on the solubility of the derivatives in aqueous solution was investigated. It was found that the lower limit DS value for both water-soluble and amphiphilic derivatives decreases with increasing length of oxyethylene chains. The amphiphilic derivatives, which are soluble in both water and chloroform, precipitate out of aqueous solution on heating without gel forming, such a phase transition behavior was studied in terms of DS value, length of oxyethylene and concentration. The precipitation temperature (Tp) of the amphiphilic derivatives is range from 54°C to 96°C. It decreases with increasing the total DS value, and increases with an increase in the length of oxyethylene chains. The Tp value of the derivatives was found to be almost independent in the concentration range of 1–15 wt %, however the Tp value increases sharply with decreasing polymer concentration when the concentration is lower than 1 wt%.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002890070011

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Separation of trans-1,4, cis-1,4 and 1,2-vinyl polybutadienes by thin layer chromatographyDedicated to Professor Dr. ICHIRO SAKURADA at the occasion of his 70th birthday (1974)

Donkai, Nobuo ; Murayama, Nobumichi ; Miyamoto, Takeaki ; [et al.]

New York : Wiley-Blackwell

Die Makromolekulare Chemie 175 (1974), S. 187-195

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ISSN: 0025-116X

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Description / Table of Contents: Es wurde eine Untersuchung über die dünnschicht-chromatographische Trennung von Polybutadienpräparaten mit den drei unterschiedlichen Mikrostrukturen, trans-1,4-, cis-1,4-und 1,2-Vinyl, durchgeführt. Um diese drei Polymerproben chromatographisch zu trennen, wurde ein experimentelles Verfahren ausgearbeitet, bei dem Tetrachlorkohlenstoff und Amylchlorid wechselweise als Laufmittel verwendet wurden. Ferner wurde gezeigt, daß dieses Verfahren in Kombination mit einer zweidimensionalen Entwicklungstechnik eine Auftrennung des ternären Polymergemisches in die einzelnen Komponenten ermöglicht. Dazu wurde das chromatographische Verhalten von sogenannten „equibinären“ Polybutadienen unter Anwendung des bislang ausgearbeiteten Verfahrens untersucht.

Notes: A study on thin layer chromatographic (TLC) separation of polybutadienes with three different microstructures, namely, trans-1,4, cis-1,4, and 1,2-vinyl, was carried out. An experimental procedure to separate three possible binary mixtures of these polymers into each component species is established in an alternate use of carbon tetrachloride and amyl chloride as developer. Further it is shown that this procedure combined with a two-dimensional TLC development technique allows to separate the ternary polymer mixture into components. In addition, the chromatographic behavior of so-called “equibinary” polybutadienes has been investigated using the technique established so far.

Additional Material: 3 Ill.