关键词: 泥浆性能, 取代度, 羧甲基纤维素, 泥浆添加剂

Abstract: A series of carboxymethyl cellulose (CMC) Samples with a degree of substitution (DS) from 0.48 to 1.86 were synthesized and their crystallity is estimated by X-ray diffraction. The effect of added salt on the solubility of CMC in water was investigated by the turbidimetric titration method. In NaCl, KC1 and MgCl₂ solution, CMC did not precipitate. In CaCl₂ and SrCl₂ solution it was found that the higher the DS of CMC the easier the phase separetion. The M. W. of CMC had no effect on the precipitation. The phase separation was caused by the intermolecular association of CMC chains through M²⁺. The rheological behavior of CMC aqueous solution was also investigated, The apparent viscosity (η_a ) of CMC solution increases with decreasing DS in the system without added salt and drops down when salt was added particularly in the case of the CMC of low DS. The measurments of rheological curve and water-loss of CMC-treated mud indicats that in either free or added salt system, the η, plastic viscosity (η_p), yield value (τ_o) are larger for CMC with higher M.W. and DS, and the efficiency of controlling the water-loss of the treated mud is also higher.