| 摘要 |
High molecular weight copolymers of molecular weight at least about 100,000 and comprising a water-soluble polymer backbone, generally polyacrylamide, and pendant poly(alkylene oxide) groups, generally poly(ethylene oxide) groups in an amount of about 0.15 to about 3 mole %, are used as retention aids in the formation of wood pulp sheet, particularly mechanical pulp, along with conventional phenolic compounds, in place of very high molecurar weight poly(ethylene oxide) polymers. The copolymers are much less sensitive to degradation and loss of effectiveness than the poly(ethylene oxide) polymers. The retention aid copolymers may be prepared by copolymerization of monomers or by graft polymerization of poly(ethylene oxide) polymer onto the polyacrylamide backbone, using radiation.
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