Abstract: A water soluble graft copolymer useful as retention and drainage aids in papermaking processes having the structure: ##STR1## wherein E is the repeat unit obtained after polymerization of an .alpha.,.beta. ethylenically unsaturated compound, the molar percentage of a:b is from about 95:5 to 5:95, with the proviso that the sum of a and b equals 100%; G comprises the structure: ##STR2## wherein d is a cationic monomer, R.sub.1, R.sub.2 and R.sub.3 are the same or different and are hydrogen or a lower alkyl group having C.sub.1 to C.sub.3, F is the salt of an ammonium cation and the molar percentage of c:d is from 95:5 to 5:95 with the proviso that the sum of c and d equals 100%.

Abstract: An apparatus and method to simultaneously evaluate the drainage, retention and formation characteristics of paper pulp comprising mixing the paper pulp furnish in the top chamber of the apparatus, releasing the furnish into a middle chamber via a valve having a cone shaped structure for even distribution of the furnish onto a wire screen, and utilizing a time delay before opening a vent valve in order to attenuate impingement forces. The apparatus utilizes a rotating blade under the wire screen to duplicate the pulsation forces of full scale papermaking equipment, an externally applied means to assist in the removal of water similar to a paper machine couch roll. Data generated during the foregoing steps is fed into a computer to evaluate the entire free water drainage process of the furnish. The device is able to set parameters to simulate the water removal process on most paper machines via level control and duration of pertinent variables.