THERMOGELATION OF METHYLCELLULOSES - NEW EVIDENCE FOR UNDERSTANDING THE GELATION MECHANISM

Methylcelluloses are widely used for industrial purposes due to their peculiar properties. These are the consequence of associative behaviou r due to hydrophobic interactions involving highly substituted units. The properties of commercial samples with heterogeneous distribution o f the substituents and laboratory-made samples, with a more homogeneou s distribution, are compared to allow a better understanding of the th ermogelation process of methylcelluloses. Whatever the structure (degr ee of substitution, repartition of substituents and presence or not of highly substituted units) the same steps occur during this process, b ut the physicochemical observations (critical temperatures of physical changes for example) depend upon this structure. (C) 1998 Published b y Elsevier Science Ltd. All rights reserved.