Determination of Load-Bearing Element Length in Paper Using Zero/Short Span Tensile Testing, 1999 International Paper Physics Conference Proceedings

Warren Batchelor

In this work, an equation is developed to allow the average length of load-bearing elements within a sheet of paper to be estimated from zero and short-span tensile tests. This was used to examine the effect of drying treatment on the average length of load-bearing element in five furnishes: two radiata pine kraft pulps, a eucalyptus globulus kraft pulp, a eucalypt NSSC pulp and a recycled pulp. For each pulp, three sets of handsheets were made. The first set of handsheets was made from the never-dried pulps. The second set of handsheets was made by forming a set of handsheets and air drying them under restraint. The air-dried handsheets were then reslushed and made into handsheets. The third set was made by oven drying a set of handsheets, reslushing them and then forming handsheets. Zero and short span tensile strength measurements were made on the fifteen different sets of handsheets to allow the average length of load-bearing elements in each case to be calculated. For all five furnishes it was found that the average length of load-bearing element was approximately equal to the measured average fibre length, independent of the type of drying treatment used to produce the handsheets.