Abstract
Given their high strength-to-weight ratio, there is an ever-increasing volume of plastics being used in the automotive industry as plastics aid in the charge to lightweight vehicles for improved fuel efficiency. However, these plastics are often landfilled at their end-of-life, which has given rise to the demand for sustainable materials and waste management alternatives compared to purely synthetic systems. Natural fiber composites have been explored as a viable material option to reduce the environmental impact of plastic use in automobiles while simultaneously ensuring the part performance is not sacrificed. Herein, we explored the use of hemp/polypropylene (PP) composites in which US-sourced hemp is compared to internationally sourced and industrially available hemp. There appears to be a minimal impact on the composite properties regardless of fiber sourcing, and the addition of a natural filler to the PP matrix results in up to a 367% increase in Young's modulus, 126% increase in heat deflection temperature, and comparable water uptake performance. It should be noted that the natural filler addition does increase density by up to 13% due to the higher density of natural fibers compared to the low-density PP matrix. A modified rule of mixtures calculation revealed that the composite materials produced in this study demonstrated good agreement with analytical modeling. Finally, a screening analysis was performed exploring the transportation of hemp fibers, and the results build a strong case for regionalized manufacturing of automotive parts.
| Original language | English |
|---|---|
| Journal | Materials Advances |
| DOIs | |
| State | Accepted/In press - 2025 |
Funding
This research was supported by the U.S. Department of Energy (DOE), Advanced Manufacturing Office and used resources at the Manufacturing Demonstration Facility at Oak Ridge National Laboratory, a User Facility of DOE's Office of Energy Efficiency and Renewable Energy. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( https://energy.gov/downloads/doe-public-access-plan ). Microscopy studies were completed at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internships Program (SULI) administered by the Oak Ridge Institute for Science and Education. This research was supported in part by an appointment to the Oak Ridge National Laboratory GRO Program, sponsored by the U.S. Department of Energy and administered by the Oak Ridge Institute for Science and Education. The authors would like to thank the Hemp Alliance of Tennessee, Ken Meyer (Complete Hemp Processing), John Peterson (Dakota Hemp), and Corbett Miteff for their collaboration and engaging discussions around hemp fiber growing and processing. The authors would also like to thank the MiniFIBERS, Inc. team, specifically Jacob Ragland and Scott Frasca, for their guidance in natural fibers and support of the project.