Effect of highland barley distillers' grains as filler on the properties of food packaging materials

To address the issue of the disposal of highland barley distillers' grains (HBDG) and reduce resource waste and environmental pollution, using HBDG as fillers, two types of degradable food packaging composite materials were prepared: HBDG/PBS sheets composed of HBDG and the polymer resin polybutylene succinate (PBS), and kraft linerboard made by blending HBDG with unbleached sulfate pulp from broadleaf wood. The effects of adding HBDG on the microstructure, physical properties, and thermal properties of the prepared composite materials were explored. The results showed that the HBDG powder extracted by supercritical CO₂ had better interfacial compatibility with PBS than the unextracted HBDG, and the properties of the prepared materials were superior. Compared with the pure PBS sheet of the control group, the mechanical properties and moisture resistance of the HBDG/PBS composite materials decreased with the increase of HBDG addition, but the thermal stability increased. In addition, compared with the control group, the mechanical properties of the kraft linerboard made by blending HBDG powder decreased with the increase of HBDG addition, while the thermal stability remained unchanged. When the HBDG addition was 20%, it still met the national first-class standard for kraft linerboard. The resin composite materials and paper-based composite materials obtained in this study could meet the requirements of production applications within a certain range, which was of great significance for the use of HBDG in the preparation of new food packaging materials and high-value utilization.