a) Definition of Hemp Composites
A composite is a material made by combining at least two different types of materials that have different chemical properties. A hemp composite is made by combining a resin and hemp fibers. The resin can either be 100% non-renewable, a combination of a renewable and a non-renewable resin or 100% renewable resin. In this regard, hemp is used as a reinforcement in other composites. The blending of hemp is done with other materials including thermoplastics, PLA (Polylactic acid), or thermoset fibers.
Whereas other composites are man-made and that is why they are called synthetic, hemp composite is made from natural fiber. Hemp fiber is a good reinforcement material. Hemp fibers are strong and stiff and have the mechanical properties required to perform as reinforcement materials. They also function mechanically like glass fibers. Various applications use hemp as a reinforcement in composites including furniture, automotive interior parts, and other consumer products. Mineral based composite and injection molding technologies also use hemp composites.
Comparison Between Hemp Composites and Conventional Composites
Conventional composites include Kevlar fiber, boron fiber, and carbon fiber. However, these materials are synthetic in nature. Hemp composites are a good alternative to current composites especially glass fiber composites. Conventional composites are non-biodegradable. Therefore, their disposal is an environmental hazard. Whereas natural composites take a maximum of two years to fully degrade, plastics made from petroleum take hundreds of years to fully disintegrate. Therefore, conventional composites require clear guidelines about their recycle and disposal because they are non-biodegradable materials. Instead of trying to figure out how to dispose synthetic composites, it is better to use a natural fiber like hemp. Hemp products usually meet waste management requirements.
Global warming is as a result of many factors. Some primary contributors are production of non-biodegradable products and cutting of forests. Hemp farming and its use as a technical product reduces the effects of global warming. Hemp composites should be made with a combination of materials that are fully biodegradable, for example Polylactic acid (PLA). PLA is a renewable thermoplastic made from fermented plant starches like sugarcane, corn or cassava.
Hemp composite reinforcements are natural and biodegradable. They are strong and durable and that means that they don’t compromise on functionality. Besides, they have other good features that conventional composites don’t have. Hemp composites are lighter in weight, more affordable, and planet-friendly.
Producing Hemp Bio-Composites
There are two ways of producing hemp composites. They can be made directly from hemp fibers. Alternatively, hemp textile industries can channel a by-product from the extraction of hemp fabric for use as a material for producing hemp composite reinforcements.
Instead of disposing it, the by-product can be made into other natural products like hemp composites.
b) History of Hemp Composites
In ancient times, hemp fiber was used for production of papers, textile, and ropes. There was no requirement for hemp composites in manufacturing processes in the past. Development of mechanical machines namely airplanes, cars and other machines requiring composites was done in the industrial age. Plastics invention was in the early 1900s. In fact, it is after the development of plastics that there was a need for a stronger material.
The invention of composites came about because plastics were weak and could not support some structural applications by itself. Reinforcements were important to support the plastic material. The beginning of composites began when Owens Corning made the first glass fiber in 1935.
c) The future of Hemp Composites
The global use of composites reinforced with natural materials is growing annually. The composites are made from plant and animal materials. Apart from hemp, jute, flax, oil palm, and sisal can also produce composites.
Most natural fibers have various drawbacks including poor fire resistance properties, higher water absorption, some have low mechanical properties. Some of the drawbacks can be overcome by treating the composites. Natural composites, on the other hand, are advantageous over synthetic fibers. They are cheaper, have fewer health hazards, are low in weight, are abundant in supply in comparison to synthetic materials and they are biodegradable.
Many industries are now using natural composites including aerospace, bicycle framing, decking, window framing, and the building and construction industry. In the manufacture of cars, several car manufacturers in German, the USA, and Malaysia are using natural bio-composites.
In the future, manufacturers will prefer hemp bio-composites to other natural fibers because of its advantages. There were restrictions on growing hemp in the past. Following the passing of the 2018 Farm Bill, hemp will play a bigger role in the manufacture of bio-composites worldwide. This is especially because more farmers will grow the crop. Hemp takes a short time to reach full maturity, it has good mechanical properties and it is fire resistant. Additionally, the plant does not use plenty of water during farming, hemp uses few agro-chemicals too and it adds to the fertility of the soil. More so, hemp releases a lot of oxygen into the environment by absorbing carbon dioxide during photosynthesis.
d) Frequently Asked Questions on Hemp Composites
How do you make hemp composites?
How to make hemp composite differs from manufacturer to manufacturer. But basically, hemp fiber reinforced composites are made from hemp fiber. Alternatively, they can be made from a by-product of hemp, derived from the extraction of fabric from hemp.
Are hemp composites durable?
Hemp composites are strong and durable. Hemp fiber is a strong material and products derived from hemp fiber are strong.
Why are hemp composites not popular?
This is because, in the past, hemp’s association with marijuana put restrictions on hemp farming in the USA and in most parts of the world. We expect the status to change because hemp is now classified as an ordinary agricultural plant.