Paper Tear Strength

Paper tear strength depends on the
(1) no of bonding of fibers,
(2) the length of fibers, and the
(3) no of fibers in the paper (density).


Q1 Why fibers easy to break after beating process?
ans:
1- this is due to shorter fiber will lower the fiber strength
2- the destruction of fibers become weak after beating
3- low in energy transfer cause fibers to break


Q2 Slightly beating helps to increase paper tear strength, why?
ans:
1- there is no rupture of fibers occurred in slightly beating process, which is, the length of fibers not really affected. Slightly beating process will cause internal and external fibrillation which will increase the bonding between fibers and the flexibility of fibers.
2- when flexibility ↑, bonding ↑, no change in fiber str, shear str ↑, therefore the tear str also ↑


Q3 Why fine beating will lower the tear strength?
ans:
1- fine beating will ↓ the length of fibers. length of fibers ↓ will cause the strength of fibers ↓. Strong bonding strength will not break easily, but weak fiber str wil cause the rupture of fibers.
force that need to break short fibers are lower than the force that need to break fiber-bond.
2- fiber length ↓, fiber strength ↓, fiber bonding ↑↑, force only concentrated on one spot, energy transfer ↓, fiber easy break, tear str ↓