Effect of cereal straw fiber addition to papermaking furnish

Cereal straw was processed using either a traditional soda AQ pulping process followed by DED bleaching or Organosolv pulping and several subsequent peroxide stages. Both pulps were used in an extensive lab study to evaluate the effect of cereal straw pulp addition to a traditional wood fiber furnish. The furnish compositions used in the study were based on two typical, but very different, paper grades; a printing and writing and a lightweight coated sheet. 0-30% cereal straw addition was used. Properties such as tensile, tear index, freeness, scattering coefficient and brightness were evaluated. As expected, paper properties are not always linearly related to cereal straw content. A detailed statistical model capable of predicting paper properties at different cereal straw addition levels was developed. Noticeable drawbacks with cereal straw addition were a drop in tear index and freeness. It was possible to eliminate these effects by optimization of beating intensity for the wood fibers, especially softwood fibers. In all cases it was possible to optimize process conditions in a way that 10% or more cereal straw addition could be accomplished without significant changes in paper properties.