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Summary: Water‐soluble, partially hydrophobized derivatives of O‐(carboxymethyl)cellulose (CMC) were prepared by esterification of CMC in its ‘gel suspension’ form. The classical esterification method (A) using stearoyl chloride/pyridine as well as two unconventional methods based on reaction with mixed anhydrides (B) and transesterification with vinyl laurate (C) respectively, were compared in terms of the structural, molecular and performance properties of the obtained derivatives. The classical esterification and method B yielded water‐soluble simple fatty acid esters, whereas mixed acetic‐fatty acid esters were obtained by method C. In all cases, molecular degradation of CMC was observed. 1H and 13C NMR spectroscopy of the acetyl‐lauroyl derivatives of CMC with a degree of esterification DSE of 0.20 indicated a prevalence of the lauroyl groups (DSAc:DSLa = 0.03:0.17). Most of the water‐soluble derivatives exhibited excellent emulsifying efficiency. They represent polysaccharide‐based surfactants with effective anti‐redeposition properties as well as good washing power. Suitable derivatives can be prepared under mild reaction conditions by both unconventional methods which implies that they have potential as substitutes for the expensive and invasive conventional method.Preparation of CMC derivatives.magnified imagePreparation of CMC derivatives.

Polymeric biosurfactants were prepared by the transesterification reaction between rapeseed oil triacyl glycerides and carboxymethylcellulose (CMC). The reaction was performed in H2O/N,N dimethylformamide (DMF) with potassium laurate as catalyst at various reaction conditions using microwave radiation as heating source. The structural features of the obtained water‐soluble CMC derivatives were characterized Fourier‐transform infrared (FT‐IR) spectroscopy and their behavior in dilute aqueous solutions was investigated by surface activity measurements, viscometry and with a polarity probe, the Coomassie Brilliant Blue dye. All derivatives showed a very low esterification extent and moderate surface tension lowering effect. Nevertheless, they exhibited significant emulsifying efficiency comparable to that of the synthetic surfactant, Tween 20. They establish hydrophobic associations in bulk solution while adsorbing on the air/water interface. The presence of hydrophobic substituents in CMC molecules enhanced the hydrophobicity resulting in higher emulsion stability than produced by Tween 20. The results suggested that suitable polymeric biosurfactants applicable as emulsifying agents can be prepared from CMC under microwave heating at low microwave power and reaction times in the range of few minutes, what represents a great advantage in comparison with transesterification reactions lasting up to 6 h at conventional heating. POLYM. ENG. SCI., 2011. ©2011 Society of Plastics Engineers.

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