PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 2, Number 1, 2016
though its ash content was similar to the ash content of B and F. Compared with C-PAMs B and F, C-PAM C contained a low charge density, suggesting that charge density was an important factor in first-pass retention and strength. The molecular weight of the C-PAMs was also important. The molecular weight of C-PAM B was lower than that of C-PAM F. Of the six C-PAMs, the molecular weight of C-PAM B was the median value. This result indicated that the C-PAM with the highest charge density should also have a molecular weight that is higher than average in order to improve both first-pass retention and paper strength. The charge density of a C-PAM, which acts as a retention aid, is more important than its molecular weight for improving the first-pass retention and strength of white ledger sheets. The charge density must be sufficiently high to allow the CPAM to gather anionic fine particles.
Fig. 7. First-pass retention values of white ledger with different dosages and types of C- PAMs
Fig. 8. Breaking length as a function of ash content in handsheets made from white ledger and C-PAMs
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Article 1 – Improving Retention and Strength
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