Location: Cotton Ginning Research
Project Number: 6066-30600-001-003-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 29, 2026
End Date: Sep 28, 2028
Objective:
The objective of this project is to build upon previous work to develop methods to characterize industrial hemp fibers. Objectives will focus on the use of both existing technologies and the development of novel methodologies and procedures. Development of characterization procedures and methods to characterize industrial hemp fiber is critical to the development of a domestic industrial hemp industry which will provide a new crop and revenue stream to increase profitability for American producers and farmers, in keeping with the research priorities of the Secretary of Agriculture.
Objective 1 - Expand previous work to validate measurements of fiber length and diameter.
Objective 2 - Develop methodologies for determining individual hemp fiber tensile properties.
Objective 3 - Develop a standard procedure for sample preparation of hemp fibers for tensile testing.
Objective 4 - Assess image analysis approaches to measuring fiber length.
Objective 5 - Assess image analysis to evaluate fiber/hurd content (cleanliness) with a focus on measuring efficacy of decortication processes in producing individualized hemp fibers.
Approach:
Objective 1 will be accomplished using a commercial optical fiber analyzer instrument. The Cooperator has performed preliminary work to measure industrial hemp fiber with this instrument; however, that work has been limited based on the constraints of the instrument in processing only highly refined samples which limited the amount of data produced. The Cooperator will expand on previous work and increase the number and diversity of samples while validating the method for suitability with industrial hemp fibers.
Objective 2 explores the use of existing instrumentation for measuring the tensile properties of individual hemp fibers. A small-scale tensile tester with high resolution will be used for initial measurements. Hemp fibers reportedly possess high strength with low elongation, however the nature of hemp fiber as bundles of finer fibers connected by connective tissues, and the high variability in fiber diameter and sample uniformity will present challenges in properly assessing tensile properties. Single fibers will be separated from larger samples and measurements on breaking force, breaking elongation, and normalized breaking load (tenacity) will be made. Analysis will determine the minimum number of fibers needed to represent a larger sample, testing conditions such as pre-load force, crosshead speed, clamp force and clamp face material, to prevent slippage and generate valid data.
To accomplish Objective 3, results from Objective 2 will be examined. A standard procedure for industrial hemp fiber sample preparation for tensile testing will be developed. Understanding the variability within a larger sample is important to determine the number of fibers which need to be tested. The nature of the fibers themselves will be examined to determine the best practices for sample preparation. Fiber shape influences fiber slippage in the case of testing multiple fibers together in a bundle test, which is the most common approach for measuring fiber tensile properties. In single fiber tensile testing, fiber-to-fiber slippage is not a concern but the appropriate number of fibers to be tested, the pre-load force, and the separation and selection of individual fibers from a larger sample are key concerns. A standard procedure for sample preparation will improve the accuracy and repeatability of tensile testing of industrial fibers, which is an important consideration for the commercial trade of fibers.
Objectives 4 and 5 will be performed using commercially available scanners or standard digital image capturing technologies. Industrial hemp fiber samples will be distributed across the bed of a scanner or across another surface before a digital image is captured. Fiber length measurements (Objective 4) will be performed using image analysis in which single fibers are identified and isolated from other fibers within the image. This method has the potential to measure a large number of fibers efficiently but will require digitally separating and tracing individual fibers from a larger sample. The same image will be assessed for identifying the presence, both amount and type, of non-fibrous content, such as the woody hurd material.