摘要：

Paper or paperboard are produced from an aqueous pulp suspension which contains, in an amount effective to enhance the retention and drainage of the pulp suspension, a novel drainage/retention aid which includes: a) microparticles; and b) a polymer derived from a homopolymer of N-vinylamide having recurring units of general formula (I) wherein each R is independently selected from H or C1 to C3 alkyl and wherein n is an integer such that the absolute molecular weight of the polymer is at least 10,000 and which, prior to its addition to the pulp suspension, said polymer has been hydrolyzed to provide a charge density in the range 5 to 24 mEq/g.

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