Study On Synethsis Of MPAM And Its Retention And Drainage Mechanism

Accompany with the enhancement of inorganic salt in the wet-end, there comes the decreasing in retention and drainage capacity of CPAM. CPAM is a kind of linear macromolecule that has low positive charge density, high molecular weight. It is easy to become curling by the effect of high electrical conductivity. PDADMAC has high positive charge density, but its retention application is restricted by the low molecular weight. In this paper, retention and drainage agent MPAM was prepared by aqueous phase polymerization of DADMAC and AM, it incorporated the advantage of CPAM and PDADMAC. At the same time, this paper was investigated the retention and drainage effects of MPAM and its environment compatibility. Main results as follows:At 700C, nAM∶nDMDAAC=1∶1, the concentration of DADMAC and AM was 50%, the dosage of initiator AIBA·2HCl was 0.25%, the relative molecular weight of MPAM was 868,800. If continuous feeding of AM was used, the relative molecular weight of MPAM could attain 1,501,000, and the cationicity viscosity could attain 2.60meq/g.In the wide extension of pH value, high conductivity, MPAM with relative molecular weight of 1,501,000 basically maintain the positive charge density approximately in 2.6meq/g. The comparison of both MPAM and CPAM in retention and drainage effect indicated that: When the pH value raised from 3 to 9, the retention and the Canadian Standard Freeness of stock using MPAM has reduced form 77.91% and 345ml to 72.43% and 290ml. In the same time, the retention and the Canadian Standard Freeness of stock using commercial CPAM has reduced form 79.12% and 355ml to 65.51% and 270ml. When the stock was fluctuated between inorganic salt free and conductivity was 5140us/cm, the retention and the Canadian Standard Freeness of stock using MPAM has reduced form 73.03% and 290ml to 71.52% and 250ml. In the same range, the retention and the Canadian Standard Freeness of stock using commercial CPAM has reduced form 75.1% and 340ml to 68.61% and 210ml. When the DCS consistency was 1%, the retention and the Canadian Standard Freeness of stock using MPAM with relative molecular weight of 1,501,000 has reduced form 73.03% and 290ml to 67.69% and 265ml. In the same time, the retention and the Canadian Standard Freeness of stock using commercial CPAM has reduced form 75.1% and 340ml to 61.43% and 240ml.So MPAM's molecular weight was lower than CPAM, the retention and drainage ability was weaker, but it had excellent retention and drainage ability when the inorganic salt or the DCS consistency was high.