Wheat straw as an alternative pulp fiber

Abstract

The desire to market sustainable packaging materials has led to an interest in the use of various fiber types as a raw material. It has been suggested that the use of annual crops for partial replacement of wood fiber would result in more sustainable products. Several life cycle analyses (LCA) have been performed to evaluate these claims. These LCAs provided conflicting and contradictory results because of the local conditions and the spe-cific pulping processes investigated. Selected LCAs are reviewed and the underlying reasons for these conflicting results are analyzed. Of all the agriculturally sourced annual fibers available, other than wood, only straw pulp is currently available in commercial quantities. A careful review of the available data suggests that neither an annual crop nor wood are more sustainable in general. Countries that allow burning of straw after harvest present a unique situation. Each situation needs specific and direct comparisons that are not generally available. The use of straw fiber in place of wood fiber does not appear to present any advantages to either the environmental impact of production or to the final product quality. The impact of substitution of straw fiber for hardwood pulp in bleached board applications and for high yield pine in linerboard applications has been examined in handsheet studies. In general, the partial substitution of straw pulp for wood pulp does not improve the handsheet physical properties. These studies suggest that straw pulp should be used in low fiber strength requirement applications, such as tissue and molded fiber products. Commercial progress of straw pulping by Kimberly-Clark and Essity in low fiber strength requirement applications is a sign that the nonwood fiber opportunity has growth potential.