Effect of Curdlan on the Rheological Properties of Hydroxypropyl Methylcellulose

This work focuses on the effect of curdlan (CL) on dynamic viscoelastic property, thermal reversible property, viscosity, and the fluid types of hydroxypropyl methylcellulose (HPMC) at different temperatures. Compared to the blends at 25 °C, the blends had a smaller linear viscoelastic region (LVR), a higher gel strength, and larger storage modulus (G’) and loss modulus (G”) values at 82 °C. G’, G”, gel strength, and viscosity increased with the increase of CL. Repeated temperature sweep led to increased G’ and G” of HPMC/CL blends. For HC6 and HC8, the gel formation temperature of the repeated temperature sweep was significantly lower than that of the first sweep. The samples at 82 °C, except for the sample with 8% CL, were all yield-shear thinning fluids, and the samples at 40 °C were shear thinning fluids. The creation of HPMC/CL and its rheological research might provide some methodological references for the study of other thermal–thermal gel blends.

Deformation Index—Concept for Hysteretic Energy-Loss Process

The concept of deformation index can be effectively used to determine the relevant dynamic viscoelastic property which best correlates with the performance of the rubbery material. The concept also indicates the type of deformation that may govern a complex energy loss process, although, in this study, the underlying physical process was not experimentally identified.