Nanocellulose from Hemp: Characterization for Molded Pulp Applications

Abstract

The global shift to sustainable packaging solutions has generated growing attention towards biodegradable substitutes for traditional plastic materials. Molded pulp products, originating from lignocellulosic fibers, are both biodegradable and recyclable; however, they frequently demonstrate inadequate mechanical strength and moisture resistance, which restricts their use in high-performance packaging applications. This study explores the capabilities of cellulose nanofibers (CNF) as a reinforcing additive to enhance the characteristics of molded pulp. CNF was generated from multiple hemp-derived sources through Masuko grinding at varying pass levels and characterized using centrifugation-based techniques, such as water retention value (WRV) and settling volume, to assess their degree of fibrillation and dispersion. TEM analysis validated the findings from the centrifugation-based techniques, confirming that the trends noted in settling volume and WRV correspond to fibrillation quality at the nanoscale. Among the samples evaluated, Dry Anka Bast processed at 12 passes exhibited exceptional dispersion characteristics and was chosen for further application. CNF was integrated into molded pulp of four types: softwood, hardwood, thermo-mechanical eucalyptus pulp (TMP), and kraft eucalyptus pulp. Mechanical testing was performed to evaluate the impact of CNF incorporation on tensile strength and structural integrity. The findings indicated that CNF markedly improved the mechanical properties of molded pulp, especially in both softwood and hardwood samples, where there was a notable increase in tensile strength. Tensile strength increased from 4 MPa to 13 MPa in hardwood pulp, from 4 MPa to 18 Mpa in softwood pulp, from 3 MPa to 14 MPa in Kraft Eucalyptus pulp, and from 1 MPa to 3 MPa in TMP Eucalypts. The findings validate the enhancing capabilities of CNF and emphasize the significance of the CNF source and processing conditions in maximizing the performance of molded pulp. The results of this study contribute to the development of efficient, bio-based packaging solutions and support wider initiatives aimed at minimizing plastic waste via sustainable material innovation.