STUDY ON THE CHARACTERIZATION OF DISTRIBUTION OF SUBSTITUENTS ALONG THE CHAINOF CARBOXYMETHYL CELLULOSE

Four new paranmeters, and , and have been proposed to describe the average length of the sequence of substituted anhydroglucose units and that of unsubstituted ones respectively along the CMC chain. The methods for determining those parameters have also been presented . Six CMC samples have been characterized in terms of intrinsic viscosity, degree of substitution (DS), index of substitution(SI)_ and . It has been proved experimentally that, not only can describe the sequence distribution along the CMC chain, but also can be used for calculating SI and estimating the average degree of substitution in the substituted glucose rings.     

动态渗透压法测定水溶性聚电解质的分子量

用动态渗透压法,在适量含盐的水溶液中测量聚电解质——尿素改性磺化酚醛(SPU)的分子量。选取预计平衡点附近所作H-dv/dt的上升线为基准来测定溶液的平衡渗透压。从陶南渗透压求得SPU和第二维利系数A_2,比一般统计线团的A_2大,由A_2算得的Z~2/C'_s值,表征聚离子上有效荷电情况,其大小次序与样品处理钻井泥浆的降失水性能相一致,即Z~2/C'_s数值大则泥浆失水量小。因此, Z~2/C'_s值是聚电解质特性的一个有意义的量。