Eucalyptus Fiber Morphology and Inter Fibre Hydrogen Bond Density
Eucalyptus fiber collapse and hydrogen bond density dictate sheet tensile strength, bulk retention, and landed sheet cost in commercial packaging grades.
Page Equation
Structural Formula
Mathematical models that calculate the tensile strength of paper webs combine the strength of individual cellulose fibres with the strength of their internal bonds. The page equation provides the formula for predicting how these two distinct factors determine the total tensile strength of a sheet.
Physical Variable
This mathematical relationship shows that paper strength is limited by both the strength of the fibres themselves and the adhesion between them. The page equation uses variables representing the average fibre length, the cross-sectional area of the fibres and the zero-span tensile strength. It also includes the bonded area, which relates to the refining level of the pulp.
Mill Application
Paper manufacturers use this relationship to determine whether to invest in longer fibres or to refine the current pulp more intensively to hit their strength targets. If the fibres are already strong but the bonds are weak, additional refining improves paper strength, which is captured by the shifts in the page equation variables. Conversely, when fibre strength is the bottleneck, the formula guides the mill to blend in stronger, unbleached kraft pulps.
Balancing these variables helps mills produce lightweight boards that still meet the high-speed requirements of modern printing presses.