Homogeneous fibers from hop stems via steam explosion: advancing a novel bioresource

Abstract

Hop stems, produced in large quantities during hop cultivation, represent a largely unused agricultural by-product despite their high lignocellulosic potential. Their bast fibers have been relatively unexploited for sustainable materials. In this work, hop bast fibers are used as sustainable lignocellulosic material to assess its potential in material application. evaluates the potential of hop bast fibers as a sustainable lignocellulosic resource for material applications. Fibers were obtained through 14-day retting, mechanical decortication, carding, refinement, and hydrothermal pretreatments. Fibers were analyzed using scanning electron microscopy (SEM), and mechanical, physical, and chemical analysis to determine the best processing conditions. With 5 g/L NaOH treated with steam explosion produced the best fiber quality, yielding a small diameter range (15–45 um), minimal coarse bundles, and a fiber length of 3.51 ± 1.09 mm. Furthermore, these fibers exhibited the best mechanical properties with 512 ± 85 MPa tensile strength, 7.9 ± 0.81 GPa modulus, and 2.81 ± 0.12% elongation. These results confirm that the combination of mild alkaline pretreatment and steam explosion has a substantial effect and significantly improves hop fiber quality and supports its potential use in sustainable material applications. These properties are particularly suitable for textile, spinning and yarn applications.