Natural Fiber Composites (NFCs)

The increase in awareness of the damage caused by synthetic materials on the environment has led to the development of eco-friendly materials. The researchers have shown a lot of interest in developing materials which can replace synthetic materials. As a result, there is an increase in demand for commercial use of natural fiber-based composites in recent years for various industrial sectors. Natural fibers are sustainable materials which are easily available in nature and have advantages like low- cost, lightweight, renewability, biodegradability, and high specific properties. The sustainability of the natural fiber-based composite materials has led to an upsurge in its applications in various manufacturing sectors (Nassar, Arunachalam & Alzebdeh, 2016).

The natural fiber is any hairlike raw material directly obtainable from an animal, vegetable, or mineral source and convertible into nonwoven fabrics such as felt or paper or, after spinning into yarns, into woven cloth. A natural fiber may be further defined as an agglomeration of cells in which the diameter is negligible in comparison with the length. Although nature abounds in fibrous materials, especially cellulosic types such as cotton, wool, grains, and straw, only a small number can be used for textile products or other industrial purposes (Nassar, Arunachalam & Alzebdeh, 2016).

Plant Fiber Source

Plants that generate natural fibers are categorized as primary or secondary based on how they are used. Primary plants are those that are grown for their fiber content, while secondary plants are those that produce fiber as a by-product. Main plants include jute, cotton, kenaf, and sisal. Primary plants include pineapple, oil palm, and coir.

There are many different plant fibers in the world, mostly composed of cellulose. the below table shows the list of natural fibrous plants and the countries they are grown in.

Table 1 Countries in which the natural fibrous plants are grown (Wikipedia contributors, 2021)

According to the above table plant fibers that are abundantly available in India are date palm, pineapple, areca, coconut, bamboo, bagasse, sisal, roselle, kenaf, cotton, jute and flax. Some of the most common fibers which are widely used today are cotton, jute, coconut, jute and flax.


Fig. 14 Banana tree plantation (Nichols, 2017)


Fig. 16 Separation of banana stem for fiber extraction
(Banana fiber as a renewable resource, 2016 ).


Fig. 15 Banana fibers dried in sun (Steele, 2019)

• Pineapple

The pineapple is one of the world's most important commercial fruit crops. Because of its excellent flavor and taste, it is known as the "Queen of Fruits." Pineapple is high in calcium, potassium, vitamin C, carbohydrates, crude fiber, water, and various minerals, all of which are beneficial to the digestive system and aid in maintaining a healthy weight and balanced diet. Pineapple is well-known for its ability to relieve constipation and irregular bowel movements. This is due to its high fiber content, which promotes regular and easy bowel movements. The average crude fiber content of pineapple pulp was 0.450.03g/100g. The fruit of the Indian pineapple had a fiber content of 0.5g/100g-fw. Fiber is beneficial to the gastrointestinal tract's health, but it can bind some trace elements if consumed in excess. The major pineapple-producing countries are Thailand, Philippines, Mexico, Costa Rica, Brazil, China, Nigeria, Kenya, Indonesia, Hawaii, India, and Bangladesh (Hossain & Akhtar, 2015). The pineapple is one of the world's most important commercial crops. Its fruits are widely used in the canning industry, as well as in the production of juices and squashes for fresh consumption. In tropical and subtropical regions of the world, the pineapple plant is widely cultivated for its fruit. Pineapple leaves contain approximately 3% strong white silky fibers (Hossain & Akhtar, 2015).


Fig. 18 Pineapple farm (Cakbentra, 2021).


Fig. 17 Pineapple Leaves scrapped with a metal piece
to remove the fibers (Hijosa, 2017)

• Arecanut

Arecanut, also known as betel nut, is a widely cultivated tropical palm whose dry kernel is primarily used for mastication in India and West and Southeast Asia. India, Sri Lanka, Bangladesh, Nepal, China, Myanmar, Bhutan, Thailand, Malaysia, Indonesia, and Vietnam are the major areca nut-producing countries.

The world's current production of areca nut is 1.22 million tons from a 0.90-million-hectare area. Arecanut is grown on about 4.51 lakh hectares in India, with a production of 7.47 lakh tons of nuts and productivity of 1659 kg ha. Arecanut is primarily grown in traditional states such as Karnataka, Assam, Kerala, Maharashtra, West Bengal, and the Andaman and Nicobar Islands, but it is also grown in non-traditional areas in Karnataka and Tamil Nadu. Millions of people in rural and urban areas rely on areca nuts for their livelihood (Parthasarathy, Aswath, Nirma babu & Senthil Kumar, 2017).

Arecanut takes seven years to fully establish, and it can last for up to eighty years in the field. Arecanut produces not only the main product (betel nut) but also by-products during its life cycle (leaf sheath and areca nut husk). The main product is marketable, but the by-product is thrown away if it isn't used to make usable goods. There would be 1600 palms per hectare on average. Each palm produces 10 leaves and 11 sheaths per year on average. Due to technological advancements, it is now possible to put leaf sheaths to better use in the production of leaf plates, bowls, and spoons of various sizes.

These items are biodegradable and environmentally friendly. As many states ban plastic-based goods, areca nut-based products are gaining popularity and penetrating deeper into the consumer market. As a result, a new class of entrepreneurs has emerged in society (Patil, Chinnappa, Manjunatha & Sowmya, 2019).


Fig. 20 Areca nut tree (Sulairusydi. n.d.)


Fig. 19 Areca Leaf sheaths collected for making plates
(Baraland & William, n.d.)


Fig. 21 Fine Areca leaf sheath fibers
(Das, Chaudhuri & Singha, 2021)

• Royal Palm Tree / Roystonea Regia

Roystonea regia, also known as the Cuban royal palm or the Florida royal palm, is a palm species native to Mexico, Central America, the Caribbean, and southern Florida. It's a large and lovely palm that's grown as an ornamental tree in the tropics and subtropics. Roystonea regia is a popular tropical and subtropical ornamental plant. The seed is used to produce oil and livestock feed. Leaves are used for thatching, and wood is used for construction. It is still used in some types of so-called conventional medicine. R. Regia leaf sheath fibres were found to be comparable to sisal and banana fibres, but with a lower density, making them a potential source for lightweight composite materials (Goud & Rao, 2010).



Fiber Extraction of Royal Palm Leaf Sheath

The first step of the fiber extraction process is to collect all the fallen royal palm leaf sheaths from the ground. These sheaths are then kept in a pit filled with water for a period of 20-25 days. The royal palm leaf sheaths are kept in water for rotting the hard sheaths. Once the leaves are rotten, it becomes easy to remove fibers from the gummy lignin. The extracted fiber is then cleaned in fresh water to remove the other residues. The fibers are then kept for drying in the sun for 1 day to remove the moisture content from them. Now the extracted royal palm leaf sheaths fibers are ready to use.


Fig. 24 Fiber extraction process of Royal palm leaf sheat