Date of Award


Degree Name

Bachelor of Science


The more important of the newly developed fiberous paper making materials are bleached groundwood, West coast kraft, hardwood kraft, semichemical pulp and cotton linters. The weight factors of these fiberous materials have been determined by several different investigators, but their identification in a paper furnish is very difficult. The weight factors of cotton linters varies with the freeness of the sample, which can be determined by dying the fibers with a mixture of a direct orange and a direct blue bye. Differentiation can be made between bleached and unbleached groundwood with the Loften-Merritt stain. Staining methods cannot be used to differentiate between soda, hardwood kraft, and neutral sulphite semi-chemical pulps. Kraft cooked semi-chemical pulp gives a deeper lignin reaction with stains. Cotton linters have a thicker cell wall than long staple cotton, and unbeaten cotton linters stain a deeper blue when stained with a mixture of a direct blue and a direct orange dye. Unless the furnish has been highly beaten, West coast kraft made from Douglas fir and western hemlock can be identified by the microscopical structure of their fibers.