| Popis: |
The effect of carboxyl density (the ratio of acrylic acid and polyoxyethylene ether) upon the performance, molecular weight, and monomer conversion rate of polycarboxylate (PCE) were investigated by slump test, Gel Permeation Chromatography (GPC) and High Performance Liquid Chromatography (HPLC), respectively. The results showed that with carboxyl density increased from 2:1 to 7:1, molecular weight of PCE increased from 7968.5 to 13930.1 and the molecular weight distribution coefficient increased from 1.5 to 2. The HPLC date indicated carboxyl density does not affect the rate of monomer conversion. Test of the fluidity of cement pastes displayed that as carboxyl density was 4.0:1, PCE show the optimal dispersion and dispersion-retaining ability. |
