The influence of shear rate and rest time on the thixotropy of the complex thixotropic suspension of Fe-Al-Mg-MMH/montmorillonite

Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan, Shandong 250100, P. R. China E-mail: wghou_cn@yahoo.com.cn Manuscript received 5 November 2001. revised 28 August 2002. accepted 18 December 2002 We have studied the influence of the measuring conditions on the thixotropy of the complex thixotropic system with the weight ratio of Fe-Al-Mg-MMH-to-montmorillonite (R) being 0.051, especially the effect of the shear rate (D1) after high-intense shearing and the rest time (ts) before measuring the viscosity. The influence of Di and ts was found complex, i.e. when ts = 0, the system showed complex thixotropy when D1 was low (10. 170 s-1), whereas the thixotropic type changed to positive when DI was high (3411. 511, 1022 s-1). The viscosity decreased with increasing DI. In the studied range of ts (0-2 h), the system changed from complex thixotropy at low D1(10. 170 s-1) and positive thixotropy at high Di (340, 511, 1022 s-1) all into negative thixotropy with the prolong of 4. The viscosity decreased with 4 at low shear rate (10, 170 s-1) and increased with is at high shear rate (340, 511, 1022 s-1), respectively. The mechanism is discussed