Hemp Hurd/Medical PPE Composites: Enhancing Mechanical and Thermoplastic Characteristics

ABSTRACT The production and disposal of petrochemically derived materials have resulted in severe environmental concerns in recent decades. There is a growing interest in utilizing natural and/or recycled feedstocks to manufacture high‐performance, eco‐friendly materials for various applications. In this study, hemp hurd, a byproduct of natural hemp plant processing, was pulverized into micron‐sized particles and compounded with recycled resin from medical PPE, such as single‐use hospital gowns made of polypropylene/polyethylene (PPE). The hurd particles were compounded with PPE at an equal mass ratio through a high‐shear thermo‐mechanical process using Intelli‐Torque Plasti‐Corder, and then compression molded at 160°C. In the 50/50 hurd/PPE blend, PPE was partially replaced at 3, 5, and 10 wt% with polypropylene‐grafted‐ maleic anhydride (PPgMA). Various characteristics such as tensile stress–strain, viscoelastic, melt‐rheological, blend morphology, crystallinity, and chemical interactions of the materials were evaluated. The materials consisting of hurd (50 wt%) with particle dimensions below 38 μm showed enhanced mechanical performance with an average tensile strength of approximately 26 MPa and Young's modulus of 3 GPa when PPgMA was added at 5 wt%. The materials also exhibited good melt‐rheological behavior like traditional thermoplastics such as neat polypropylene and showed improved phase homogeneity in the presence of PPgMA. In brief, this study revealed that the hurd/PPE composite has mechanical performance and melt‐rheological properties similar to neat PPE, and the composite materials can be recycled and reprocessed using traditional thermoplastic processing instruments.