Interactions with water of mixed acetic-fatty cellulose esters

Jérôme Peydecastaing (1) , Carlos Vaca-Garcia (1) , Marie-Elisabeth Borredon (1)

1 CAI - Chimie Agro-Industrielle

Cellulose powder was acylated with mixtures containing acetic, fatty and acetic-fatty anhydrides to form acetic-fatty cellulose esters. The total degree of substitution (DS) of the mixed cellulose esters (MCE) ranged from 2x10-2 to 2.92. MCE were characterized by their interactions with water. Static contact angles with water were measured on a regular smooth surface. The values found were dependent on the fatty acyl content and independent of the acetyl content. In the case of acetic-oleic cellulose esters, the minimum DS of the oleoyl moiety required to obtain permanent water repellency was 3x10-4. The microporosity of the samples may account for this exceptional hydrophobic character. Nevertheless, water vapor adsorption measurements on powder samples revealed only a limited increase in hydrophobicity of the MCE compared to cellulose acetate with the same acetyl content. It was thus demonstrated that water repellency and vapor water adsorption are not correlated.

Mots clés: Mixed cellulose esters; Contact angle; Differential vapor sorption; Hydrophobicity; Water repellency; Low-substituted cellulose esters

Domaines: Matériaux

Jérôme Peydecastaing, Carlos Vaca-Garcia, Marie-Elisabeth Borredon. Interactions with water of mixed acetic-fatty cellulose esters. Cellulose, 2011, 18 (4), pp.1023-1031. ⟨10.1007/s10570-011-9530-2⟩. ⟨hal-02080031⟩