TO STUDY THE EFFECT OF DRY STRENGTH CHEMICAL ADDITIVES ON BENDING STIFFNESS OF PAPER BOARD

Abstract

A paper and paperboard used in packaging material. In this work single layered sheets were prepared in the laboratory from recycle pulp namely office waste, manufacturing of paper board single layer by recycled fibre were used without deinking. Further comparative analysis was performed between the strength(Bending Stiffness, Tensile Strength Index,) cPAM sheets and without cPAM sheets of 60gsm, 100gsm, 150gsm, 200gsm, 250gsm. It wasobserved that sheets which are made with different dose of cPAM have more strength (Bending Stiffness, Tensile Strength Index, and Tensile Strength) than sheets which are made without cPAM. It was also observed that optimum strength properties (bending stiffness, Tensile strength. Elastic modulus etc.),at 0.5% cPAM sheets. Further increases dose of cPAM strength properties of paper sheets start decreasing. Hence best mechanical properties of paper sheets were find at a specific value of cationic polyacrylamide which is 5kg/Tonne. It was also observed that calculated value of bending stiffness using expression (1/12×E×t3) applicable for Elastic & homogeneous materialwere in some deviation from measured bending stiffness, Possibly due to viscoelastic nature of sheets made from pulp. After that we modify expression of bending stiffness like that (1/12×E×tα) with the help of experiment results we find the valve of α which is equal to 2.96, put that value in above expression we find that value of measured bending stiffness and calculated bending stiffness are equal for all gsm sheets 60gsm, 100gsm, 150gsm, 200gsm, 250gsm which are made by office waste pulp without deinking.Regression expression have been developed for determine the bending stiffness index of a paper board made by office waste pulp with the help of expression we can find bending stiffness index for different grammage sheets by putting grammage value on expression