Written By: Carter Markey, Analyst
Composites are the combination of two or more materials (often polymers and a reinforcing material) with differing thermal and physical properties, combined to form a new material with desired properties to suit a specialized function. Bio-based composites, also called natural fiber composites, combine biopolymers with a reinforcing agent, often natural fibers (e.g., flax, hemp, bamboo), and offer a sustainable alternative to their synthetic counterparts. These bio-based materials have proven desirable due to their renewable raw materials, potential biodegradability, and low cost [1].
Figure 1: OrganoPor: bio-based insulation [2]
The main structural components of the natural fibers used in these bio-based materials are cellulose, hemicellulose, and lignin, with cellulose being the most abundant. These fibers are the main reinforcing components held together by a matrix (Biopolymer). The fibrous materials add strength to the weaker biopolymer matrix and can be derived from many plants worldwide [3].
Table 1: Examples of natural fibers and where they are sourced [4]
| Fiber Plant | Country |
| Bagasse (Sugar Cane) | India, Brazil, China |
| Bamboo | India, China, Indonesia, Malaysia, Philippines |
| Hemp | China, France, Philippines |
| Flax | Canada, France, Belgium |
| Wood Fiber | Canada, US, China |
| Rice Husk | China, India, Indonesia, Malaysia, Bangladesh |
Why Bio-Based Composites?
In a world that’s ever-changing, the demand for a greener future has never been higher. Bio-based composites play a massive role in this by reducing the environmental impact created by their synthetic counterparts. Some of the environmental advantages of substituting synthetic materials for bio-based materials include:
- Renewability: The natural fibers used in bio-based composites are plant-based and, therefore, renewable, as they can be replanted and are readily available. This helps minimize the need for non-renewable synthetic materials.
- Biodegradability: A shift towards bio-based materials can significantly reduce the amount of plastic waste around the globe, which is detrimental to our environment. While synthetic plastic can take up to 500 years to fully decompose, a bio-based packaging material only takes up to a few months.
- Reduced carbon footprint: These bio-based materials are also less strenuous to the environment in terms of their production. Synthetic materials often rely on CO2 and other fossil fuels in their production, while bio-based composites do not.
In industry today, bio-based composites are widely used for various applications. Some of these applications include:
Construction: In the construction industry, bio-based composites are widely used as insulating material to regulate the internal temperature of buildings. These materials are also used in some roofing and structural components [5].
Automotive: Bio-based composites are used in the automotive industry to replace synthetic plastics, often in the dashboard, consoles, and door panels. They can also be a substitute for materials used in seating and help reduce the overall weight, which in turn can help reduce fuel consumption [5].
Aerospace: These materials are used as a substitute for inner paneling and some structural components. The insulating properties of these materials are crucial for aerospace, and similarly to the automotive industry, offer lighter weight materials to improve fuel efficiency [5].
Product packaging: Bio-based composite materials can replace environmentally damaging synthetic plastic packaging. These bio-based materials offer biodegradable options, which in turn help reduce plastic waste [5].
Medical Field: These materials are used in implants, prosthetics, and medical devices due to their biocompatibility. They are beneficial in reducing synthetic materials used in these devices and potentially boosting tissue regeneration when used in implants [5].
Why is the Thermal Conductivity of Bio-Based Composites Important?
As aforementioned, creating these biocomposites often aims to improve the materials’ thermal and physical properties. Therefore, thermal conductivity is crucial as it directly determines a material’s ability to conduct heat.
Thermal conductivity is important for the insulating properties of bio-based composites. A good insulator requires low thermal conductivity to increase the thermal resistance, reducing the passage of heat through the material. This is extremely important for the bio-based insulation used in the construction industry and any bio-based components used in the automotive, aerospace, and food packaging industries.
How to Test Thermal Conductivity of Bio-Based Composites
C-Therm’s Trident uses transient thermal analysis testing, which offers much more versatility compared to the traditional steady-state methods. This equipment is able to test thermal data within a matter of seconds over a temperature range. In contrast, steady-state methods take a significant amount of time, 30 minutes or more, for each measurement. C-Therm’s transient thermal conductivity testing also offers the ability to analyze the thermal properties not only under different temperature conditions, but under different pressure and humidity conditions as well. Another advantage of using transient thermal analysis is regarding the sample preparation and form factor. Transient methods are able to test samples of varying shapes and sizes, whereas steady state samples have specific dimension requirements. Steady-state samples are also often required to be larger than samples prepared for transient thermal testing.
Thermal analysis using C-Therm’s Trident can be performed under 4 methods of operation, including MTPS, Flex TPS, TLS Needle, and THW Probe. Click HERE to learn more about these testing methods and their wide range of applicability.
Figure 2: C-Therm’s Trident
The transient methods offered with C-Therm’s Trident prove desirable for these bio-based composite materials because of their short testing times and reduced heat loss. Also, the ability to test under a wide range of conditions proves extremely useful for the wide array of applications and industries in which these materials are used.
For these requirements, C-Therm’s MTPS configuration is a highly effective method for determining the thermal conductivity of these materials due to its high versatility and ease of use. C-Therm’s TPS method would also prove effective, as it provides the greatest flexibility and control over experimental parameters such as test time and power.
Figure 3: C-Therm’s MTPS Sensor
Figure 4: C-Therm’s Flex TPS Sensor
Case Highlight: Insulation properties of LCNF Aerogels
Researchers at the University of British Columbia tested the thermal conductivity of lignocellulosic nanofibril aerogels using C-Therm’s MTPS configuration to determine the insulating effectiveness of this new bio-based material. The data proved accurate and within the desired thermal conductivity range [6].
Figure 5: Thermal conductivity data for LCNF-based aerogel compared to commercial insulator using C-Therm’s MTPS sensor
Case Highlight: Mycelium and Wood Chip Bio-Based Composite Insulation
C-Therm’s Trident was used to determine the thermal conductivity of mycelium and woodchip bio-based insulation by researchers at École de Technologie Supérieure at Université de Québec. The use of C-Therm’s MTPS configuration proved that the thermal conductivity value of this material was below the required limit and allowed the continuation of further research on this material [7].
Figure 6: Thermal conductivity testing being performed on mycelium and wood chip-based insulation using C-Therm’s Trident MTPS configuration [7]
Summary
- Biocomposites are a growing and necessary industry to meet the increased environmental demands.
- These materials also offer lighter-weight and lower-cost options compared to non-bio-based materials used previously.
- The thermal conductivity plays a key role in the insulating properties of these materials.
- Transient thermal conductivity testing methods would be desirable for these materials to allow the ability to test under a wide array of conditions.
Interested in Learning More?
- For more information on bio-based composites and the importance of thermal conductivity testing for these materials, check out this WEBINAR: Exploring Thermal Conductivity in Bio-Based Composites.
- Click HERE to learn more about C-Therm and their transient thermal analysis testing products.
- Click HERE to learn more about C-Therm’s thermal analysis lab testing services.
Schedule a Technical Consultation Today!
- To schedule a technical consultation with a subject matter expert, contact info@thermalanalysislabs.com.
- For any general inquiries regarding C-Therm’s Trident, sensors, or testing services, contact info@ctherm.com.
Tel: +1 (506) 457-1515
References
[1] Harries, K. A., & Sharma, B. (2019). Nonconventional and Vernacular Construction Materials: Characterization, Properties and Applications.
[2] OrganoPor: Sustainable and cost-effective thermal insulation made from natural materials
[3] Shanmugam, V., Mensah, R.A. (2021). Circular Economy in Biocomposite Development: State of the art Challenges and Emerging Trends.
[4] Elfalah, I., Abbassi, F., (2023). A comprehensive review of natural fibers and their composites: an eco-friendly alternative to conventional materials.
[5] Baltatu, M.S., Vizereanu, P. (2025). Biocomposites: Materials, Properties, and Applications.
[6] Zhu, Y., Yu, Z. (2022). Developing Flame-Retardant Lignocellulosic Nanofibrils Through Reactive Deep Eutetic Solvent Treatment for Thermal Insulation.
[7] Grenon, V., Maref, W. (2023). Multi-Property Characterization of an Experimental Material Composed of Pleurotis Ostreatus Mycelium and Ash Wood Chips Compared with Glass Wool and Hemp Wool.
About the Author
Carter Markey is an Analyst working through his co-op term at C-Therm Technologies Ltd. Upon completing his co-op, Carter will return to the University of New Brunswick to complete his final year of the Chemical Engineering program.