Effect of Basis Weight on Paper Properties of Scots Pine and European Black Pine Kraft Pulp

The physical, optical, and mechanical characteristics of handsheets made from kraft pulps of Scots pine (Pinus sylvestris L.) and European black pine (Pinus nigra Arn.) in basis weight ranging from 50 to 125 g/m2 (15 g/m2 intervals) were assessed in this study. The thickness, bulk, apparent density, opacity, burst strength, tear strength, tensile strength, stretch and tensile energy absorption (TEA) properties of papers obtained in different grammages were evaluated. The results showed that basis weight of handsheets had a significant effect of examined properties of handsheets. In both pulp samples, when the handsheet basis weight increased, the tensile strength, burst strength, tear strength, apparent density and opacity of the handsheets increased while bulk decreased. In all basis weight values, Scots pine handsheets had higher tensile and burst strengths, opacity, and apparent density than those of European black pine handsheets. Therefore, Scots pine pulps can be more suited for packaging purposes. This study shows that kraft pulps obtained from different wood species can be optimized and desired paper properties can be achieved by appropriate basis weight selections.