4 CONCLUSION
In summary, SCG was successfully used as a filler for PP to produce biomass-plastic composites. The coffee oil in SCG is removed more efficiently under air atmosphere than under nitrogen atmosphere at the same temperature. The obtained SCG holds a better affinity with PP by increasing the hydrophobicity, which further improves the water absorption, hydrophobicity, and mechanical properties of the resulting SCG/PP composite. The job offers a simple method for the preparation of biomass-plastic composites at a relatively low cost and an eco-friendly process. The composite shows potential applications in the field of food packaging.