The effects of the concentrations of methylcellulose (MC) solutions and glycerol as a additive on gel properties were investigated with rheological, test-inversion-tube, and breakthrough-vacuum methods. The results showed that glycerol favored the sol-gel transition of MC solutions, and the gel temperature was approximately proportional to the glycerol volume ratio; however, the gel strength decreased as the glycerol volume ratio increased. To further understand the gel structure, rubber elasticity theory was cited and proved to be consistent with the experimental results. (c) 2006 Wiley Periodicals, Inc.