Original, acrylamide (AA) grafted, and methyl methacrylate (MMA) grafted pulps were beaten for 3, 6, and 9 hours respectively in water, ethanol, and acetone.
Handsheets were made from them in the presence of water after removing the medium.
The relationship between paper properties and beating state were investigated mainly from the standpoint of the swellability of grafted pulp in the mediums.
1) Swellability of original and AA grafted pulps in the mediums has linear relationship to the cohesion energy density of the mediums, but in the case of MMA grafted pulp shows no linear relation.
2) Equilibrium moisture content of the paper made from grafted pulp increases somewhat with the increase of beating time.
3) Tensile strength, air resistance, smoothness, and degree of sizing of the paper made from the water beaten original and AA grafted pulps increase remarkably with increasing time of beating, while those of others increase slightly.
4) Graph of beating time vs. tear strength of the paper made from original and MMA grafted pulp shows the maximum value at 3 hours beating time irrespective of kinds of the medium, except the case of AA grafted pulp.
Mediums which have no swelling ability toward fibers do not fibrillate the grafted pulp upon mechanical treatment, while mediums which show a high or a proportionate swelling ability fibrillate the pulp in proportion to their swelling ability.
It is found that these swellability are related with the affinity between grafted polymer and organic liquid.