Rheological characterization of hydroxypropylcellulose gels

Area of Science:

• Rheology and polymer science
• Materials science

Background:

• Hydroxypropylcellulose (HPC) is a versatile polymer used in various applications.
• Understanding the rheological behavior of HPC gels is crucial for formulation development.

Purpose of the Study:

• To characterize the rheological properties of hydroxypropylcellulose (HPC) gels.
• To investigate the influence of molecular weight, concentration, and solvent composition on HPC gel rheology.
• To explore the viscoelastic behavior of HPC gels in different solvent mixtures.

Main Methods:

• Continuous shear rheometry was employed to study apparent viscosity and flow characteristics.
• Dynamic mechanical analysis (DMA) was used to examine viscoelastic behavior.
• Formulations included HPC in propylene glycol (PG), water, ethanol, and their mixtures.

Main Results:

• HPC gels exhibit shear-thinning behavior without significant yield stress or hysteresis.
• Apparent viscosity increases with HPC molecular weight and concentration.
• Higher PG content in ternary solvent mixtures enhances the elasticity of HPC gels.
• HPC gels become more non-Newtonian at higher concentrations (3%) with increased molecular weight.

Conclusions:

• The rheological properties of HPC gels are significantly influenced by polymer characteristics and solvent composition.
• A mathematical model was proposed for predicting HPC gel viscosities.
• Dynamic mechanical analysis is a valuable tool for determining zero-shear viscosities of HPC gels.