Ebringerová, Anna

Malovíková, Anna

Sroková, Iva

Tomanová, Vladimíra

English

DSpace at VSB Technical University of Ostrava

/T I !\r -�l . li .ÍI. '• iktSborník vědeckých prací Vysoké školy báňské - Technicke umvenlty 8sh a,. .. číslo I, rok 2008, ročník LI, řada hutnická článek č. 1421 SURFACE-ACTIVE AND VISCOMETRIC PROPERTIES OF HM-CMC SOLUTIONS V. TOMANOVÁ 1 *, I. SROKOVÁ2, A. MALOVJKOVÁ3, A. EBRINGEROVN1 *Facu/ty o/ lndustrial Technologies, Trenčín University o/ Alexander Dubček; 020 32 Púchov, S/ovakiae-mail: tomanova@fpt.tnuni.sk18 2 Center o/ Excellence o/ the Slovak Academy o/ Sciences, Institute o/ Chemistry,· 845 38 Bratislava, S/ovakiaABSTRACT: This contribution deals with investigation of surface-active and viscometric properties of aqueous and aqueous sodium chloride solutions of unmodified CMC and their HM-CMC derivatives. Polymeric surfactants (hydrophobically modified carboxymethylcellulose (HM-CMC)) have been prepared by chemical modification of CMC with methyl ester of rape seed oil (MERO) in reaction media H2O/DMF at various reaction conditions, under microwave irradiation with controlled power as heating source used to optimize thé preparation of water-soluble esters. The surface-active properties were studied by surface tension, critical micelle concentration and emulsifying efficiency. Most of the CMC esters exhibited very positive surface-active properties such as excellent emulsification properties for 'oil in water' type emulsions, which are comparable to that of the commercial synthetic emulsifier Tween 20. Although the derivatives do not substantially lower the surface tension of water, they form micelles in the concentration range 0.3 to 2.45 g.r 1.The viscometric properties of théir aqueous sodium chloride solutions were investigated in dilute range. The viscosities decreased due to the concentration of the HM-CMC derivatives by intramolecular interactions. KEY WORDS: carboxymethylcellulose, polymeric surfactants, associate polymers 1. INTRODUCTIONDuring the last decades, a fast growing interest in natural, biodegradable and renewable materials has been noticed because of the variety of their possible pharmaceutical, biotechnological and industrial applications. Carboxymethylcellulose (CMC)is the most important water-soluble anionic cellulose derivative of significant technical importance. Jts commercially available in large quantities and known to act as water binder, thickener, emulsion stabilizer, suspending agent and antiredeposition agent in detergents [I]. Also represents a potential biopolymer for further modification aimed to create new advanced cellulosic materials. Recently, various alternative esterification methods have been developed with the airn to avoid the use of acid halides such as esterification with mixed anhydrides prepared ''in situ" [2], transesterification with vinyl carboxylic acid esters like vinyllaurate [3] and transesterification with fatty acid methyl esters [4, 5]. In our previous papers [6, 7), attention was paid to modification of CMC by alkylation and acylation under conventional heating. Prepared derivatives of CMC were water-soluble with surface-active properties. Nowadays attention has been paid to apply the new heating system - microwave irradiation in organic and polymer chemistry [8, 9). The most important advantage is that microwave-enhanced chemical reactions are very rapid, lastjng usually a few minutes, compared to hours with classical heating methods. ln continuation of our research on partial hydrophobization of CMC using transesterification with methyl ester of rape seed oil (MERO)under microwave irradiation with ·controlled power [IO], this paper is focused on the characterization of HM-CMC solutions by surface active and viscometric measuring. 327 

Surface-active and viscometric properties of HM-CMC solutions

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Surface-active and viscometric properties of HM-CMC solutions

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