Reinforcement Fiber Production from Wheat Straw for Wastepaper-Based Packaging Using Steam Refining with Sodium Carbonate

Abstract

Locally sourced agricultural residues are a promising feedstock for the production of reinforcement fibers for wastepaper-based packaging papers. An eco-friendly high yield process to generate fibers from wheat straw using high pressure steam and sodium carbonate is presented. The wheat straw was impregnated with up to 16% of sodium carbonate and steam treated for 10 min at temperatures from 148 °C to 203 °C. The pulps were characterized concerning their chemical composition and test sheets with 100% straw fibers and with 15% and 30% straw fibers blended with recycled pulp were prepared. Fiber yields ranged from 70% to 45%, wherein more severe treatment conditions contributed to increased paper strength but lower yields. At comparable fiber yields, treatments featuring a higher chemical input, coupled with lower treatment temperatures, resulted in improved paper strength. By blending recycled pulp with up to 30% of straw fibers with a beating degree of roughly 45 °SR, the burst, compression and tensile strength was enhanced by up to 66%, 74% and 59%, respectively. As the enhancement effect decreases with a high steam treatment intensity and a high proportion of wheat straw, a moderate treatment and limited use of wheat straw may be the best choice.

The Potential Valorization of Corn Stalks by Alkaline Sequential Fractionation to Obtain Papermaking Fibers, Hemicelluloses, and Lignin—A Comprehensive Mass Balance Approach

“…Studies in the literature indicate that the presence of lignin may hinder the formation of hydrogen inter-fiber bonds which lead to reduced mechanical paper strength [ 71 ]. The mechanical strength properties showed considerably better values when compared to values obtained for a sample of recycled industrial paper (fluting, 120 g/m 2 ) (TI of 24.3 Nm/g and BI of 1.72 kPam 2 /g), proving the potential of the obtained papermaking CS fibers as either raw materials for packaging paper or as reinforcements, as already proposed by Hagel and Schütt [ 72 ]. Photos of sample laboratory paper sheets are presented in the Supplementary Materials , Figures S1–S5 .…”