Properties and fibre characterisation of bleached hemp, birch and pine pulps: a comparison

The papermaking potential of bleached kraft pulps made from hemp stalks, hemp woody-core and hemp bast fibres was studied and compared with that of bleached birch pulp and pine kraft pulp. It has been shown that among the pulps from these raw materials, hemp stalk pulp has the most useful properties for papermaking. The disadvantages of hemp woody-core pulp and hemp bast fibre pulp as papermaking intermediates proved to be low tear resistance and low tensile strength, respectively. Results indicate that the main reasons for the low tensile strength of hemp bast fibre pulp are the low susceptibility of their fibres for internal fibrillation and low hemicellulose content. The technology used in this work for the processing of hemp bast fibres into papermaking pulp made it possible to obtain pulp with high alpha-cellulose content from this fibrous raw material with a high yield in a much simpler way than when such pulps are obtained from wood.