CHIRAL CURL IN THIN PAPERS

We demonstrate that the microfibril-induced chiral curl, first observe d by Gray [1] in narrow newsprint strips, shows up in low basis weight (<50 g/m2) paper sheets of ordinary dimensions irrespective of the pa per grade. Thus at low moisture content the diagonal curl K(xy) is alm ost always positive(dagger) in thin papers. Measurements and qualitati ve analysis suggest that K(xy) is directly proportional to the degree of fibre orientation and inversely proportional to paper thickness. Ap parently, microfibrils dominate the diagonal curl in thin papers and s heet two-sidedness in thick papers or boards.