FUNDAMENTAL-STUDY OF TEAR RESISTANCE OF P ULP AND PAPER .2. RESISTANCE TO TEARING AS FUNCTION OF MORPHOLOGICAL PROPERTIES

The tear index essentially depends on the transformation of weak point s into dislocation areas. There are two kinds of weak points. The firs t one results from the presence of springwood fibre bordered pits. The second one is the accumulation of amorphous cellulose in a cross sect ion of the fibre cell well. When weak points are not transformed into dislocation areas, a good tear index may be obtained. Flexibility is a nother important factor for paper physical properties, since fibre def ormations are allowed, which produces an increase of the interfibre bo nding and the bulk of paper.