The Science of Natural Fibers- How They Work, the Benefits, and Why They're so Popular
Introduction
Fibers are materials like long, thin, and flexible thread that can be formed into yarns to produce fabrics or textiles. Textile fibers are made from different fiber types and,, thus, have different properties. Some maintain dyes exceptionally well, some are more resilient, some are softer, and some hold heat more than others.
Fibers also refer to the parts of food materials that the body cannot digest. However, they help remove gut waste. Dietary fiber can be obtained from vegetables, seeds, grains, legumes, etc.
Fibers can be grouped into synthetic fibers and natural fibers. This article will focus on natural fibers, how they work, their uses and benefits, and why they are so popular.
Natural fibers or Natural Fibres
Natural fibers are made up of long, chain-like molecules called polymers. Weaker bonds hold these polymers together, making the fibers strong and flexible. This feature gives natural fibers the ability to absorb moisture, making them ideal for clothing and other textile applications. Synthetic fibers are man-made fibers that are produced in the laboratory.
Natural fibers are classified based on their origin. Two main classes or examples of natural fibers are cellulose and protein. Cellulose is plants' most abundant natural fiber, such as cotton, flax, etc. On the other hand, protein fibers are derived from animals and include wool, silk, and cashmere.
Each type of natural fiber has its unique properties. For example, plant fibers are known for their absorbency, while protein fibers are prized for their strength and durability. Natural fibers are biodegradable and won't pollute the environment like synthetic fibers. Also, natural fibers are commonly more luxurious than synthetic fibers.
Classification and Properties of Natural Fibers
One can categorize natural fibers per their point of origin. Cotton, flax, and jute are examples of important plant fibers that belong to the class known as cellulose-base or vegetable fibers. Wool, mohair, and silk are animal fibers, often protein-based fibers. Asbestos is a mineral that belongs to the class of significant fibers.
Natural fiber composites are materials that use plant-based fibers as reinforcement. These fibers can come from various sources, including bamboo, hemp, flax, and jute. Natural fiber composites typically have superior physical properties to synthetic materials, including improved tensile strength and stiffness. However, they are also often more expensive and difficult to produce on a large scale.
The vegetable fibers can be broken down into several subcategories based on where in the plant they originated. Cotton, kapok, and coir are some examples of fibers that originated as hairs borne on the fruit's seeds or inner walls. Each fiber is composed of a single, long, and thin cell in these cases. Bast fibers are found in the inner bast tissue of the stems of certain plants and are made up of overlapping cells. Flax, hemp, jute, and ramie are examples of bast fibers. Abaca, henequen, and sisal are all types of fibers found in the fibrovascular system of the leaves of certain plants. Chemically speaking, the primary component of all vegetable fibers is cellulose. However, vegetable fibers also contain variable levels of other compounds, such as hemicellulose, lignin, pectins, and waxes, which must be removed or decreased during the processing of the fiber.
Except for silk, the outermost layer of an animal's epidermis is made up of fur or hair, composed entirely of proteins. This layer functions as a protective barrier against the environment. The larvae of moths produce silk strands, which are then utilized to spin the cocoons that they will pupate in.
Natural fibers, except mineral fibers, strongly attract water in their liquid and vaporous forms. Because of this strong affinity, the fibers enlarge as they take up water, which makes it easier to dye in solutions that contain water.
In contrast to the vast majority of synthetic fibers, all-natural fibers do not exhibit thermoplasticity; this means they do not become more malleable when exposed to heat. They show little sensitivity to dry heat at temperatures below the point at which they will decompose. There is no shrinkage or high extensibility upon heating, nor do they become brittle if cooled to below-freezing temperatures. This is because they are heated to temperatures above the point at which they will decompose. Natural fibers tend to be yellow when exposed to sunshine and dampness; loss of strength can come from prolonged contact with these elements.
All natural fibers, including mildew and rot, are especially vulnerable to the degradation processes caused by microbes. Aerobic bacteria, which can only survive in the presence of oxygen, and fungi are responsible for the breakdown of cellulosic fibers. Under high humidity and high-temperature conditions, cellulose quickly mildew and decomposes, accelerating without light. Microbes like bacteria and mold can decompose even wool and silk if the conditions are right. Moths and carpet beetles are two types of insects that can cause harm to animal fibers. Cellulose fibers are susceptible to assault by termites and silverfish. The substrate of the fiber can be chemically modified to protect against microbial damage and insect attacks; recent advances in technology have made it possible to treat natural fibers to render them essentially impervious to such damage.
Reinforced Composites and Mechanical Properties of Natural Fiber
Natural fibers are high aspect ratio materials naturally occurring and resemble hair or thread. Natural fibers are divided into three groups based on their origin: animal fibers (silk), vegetable fibers (abaca), and mineral fibers. It is generally known that natural fibers are currently on the verge of replacing synthetic fibers (glass fibers, carbon fiber, etc.) in many areas of application due to their advantages, including low cost, low weight, and biodegradability. Plant fibers are one of the most significant components of polymer-based composites. This is because they are renewable, inexpensive, and biodegradable.
High-performance fibers include leaf and bast fibers. Bast fibers are taken out of the phloem or inner bark. These are also sometimes referred to as skin fibers. The leaves of plants can be used to make leaf fibers, such as the abaca fiber made from the leaves of the banana family member M. textilis. Coconut fibers are fruit fibers. These plants can be grown in large quantities to meet demand. Therefore, a surplus of fibers could be used to reinforce composite materials. Therefore, natural fiber is the most suited option to replace traditional structural materials due to its plentiful source.
Over the past few decades, numerous researchers have worked to increase awareness of natural fiber-reinforced composites. A study on the erosive behavior of epoxy-based composites reinforced with freshwater fish (Labeo rohita) scales was done in 2009. It was an uncommon attempt to use freshwater fish scales, which are usually discarded. To create a green composite with polyester as the matrix, discarded grass broom fiber was used again in 2012. Broom grass, which is tall and grows along the banks of rivers, is also known as tiger grass.
Jute has been the subject of extensive research as a composite reinforcement material. Additionally, a study revealed that jute composites made utilizing the spray-up method exhibit a wide range of improved mechanical properties. Bidirectional jute fiber epoxy composites created by hand lay-up in 2013 were examined for their mechanical and physical characteristics. In a recent 2014 study on the compressive behavior of NFC, four compressive collapse modes—micro-buckling, diamond-shaped buckling, concertina-shaped buckling, and progressive crushing—were identified.
Natural Fibre (How they work)
So, what exactly makes natural fibers so special? Let's take a closer look at the science behind these amazing materials.
Protein fibers
The other natural fiber is protein fiber, obtained from animal sources. Protein fibers are natural fibers made from natural animal sources by condensation of α-amino acids (alpha-amino acids) to produce repeating polyamide units with various substituents on the α-carbon atom.
Protein fibers have excellent characteristics of absorbing moisture and transporting it. They do not accumulate static charge and are known for their elasticity, Moderate strength, and resiliency.
The general nature of these natural protein fibers is controlled by the sequence and type of amino acids that bond together on individual protein chains. The protein fiber consists of two main groups: animal fiber, also known as keratin fiber, for example, wool and other animal hairs, and insect fiber, also known as fibroin fiber, for example, silk.
Benefits of Natural fibers
As discussed earlier, natural fibers are made from plants and animals, while synthetic fibers are made from chemical compounds (man-made). Natural fibers are popular for so many reasons. Natural fibers have various advantages for both industrial and end users.
Natural fibers are safe to wear
Natural fibers are healthier, kind to the skin, and do not irritate when exposed to the skin because they are made with materials obtained from natural sources.
Natural materials like cotton, silk, hemp, bamboo, linen, leather, feathers, wool, and rubber pose little risk of harmful chemical absorption via the skin unless they have been carelessly handled or colored. (With synthetics, you occasionally run the danger.)
Naturally breaking in, natural materials improve in comfort with use and typically look better as the fibers begin to age. You purchase a wool sweater with the expectation that it will look a little more like you in a few years and be stretchier, softer, and more comfortable.
Fibers from natural sources are better for the environment as they are sustainable for the world and tend to create a better quality of life.
Natural fibers are comfortable
Due to their lightweight, natural fibers feel more comfortable and softer to the touch. All natural fibers have a high level of absorption. If there is too much moisture, it will enable great ventilation to remove the dampness. Because of this, cotton and silk are comfortable to wear even when it's quite hot outside, and you're perspiring a lot. It won't result in skin irritation or rashes.
Natural fibers have high absorbency
Natural fibers, especially plant-based, are very absorbent. Relating to the structure that makes natural plant fibers, they are a great option to use when you want to dry a wet surface. Most plant-based natural fibers are exceptionally strong because of the structure of cellulose, which makes up natural materials. Natural fibers are an excellent choice for bed linen, clothing, reusable diapers, cosmetics, and towels because of their high absorbency.
Natural fibers are good for better healthcare
This is because they do not contain chemicals that are dangerous to human health. People with sensitive skin need to be very careful when choosing cloth. People with allergies to wool, spandex, or latex, as well as skin diseases including psoriasis, contact dermatitis, and eczema, must take particular care while choosing to clothe.
Non-natural fabrics are not soothing to cancer patients receiving radiotherapy or chemotherapy and experiencing skin responses from those therapies. To gain the most comfort and relief from blisters and rashes, they are typically recommended to wear natural textiles, preferably silk.
Skin becomes dryer with time due to the loss of collagen and natural moisture brought on by menopause and aging. As a result, people with no skin issues in their childhood experience issues with synthetic textiles.
The Popularity of Natural Fibers
The popularity of natural fibers has grown in recent years as more and more people discover the advantages of eco-friendly fiber over synthetic fibers and are looking for sustainable and eco-friendly options. Natural fibers are now popular in various applications, from clothing to home furnishings. And with the increasing demand for natural fibers, new technologies are being developed to improve their performance and make them even more versatile.
Natural fiber-reinforced polymers are expanding substantially and have promising futures in the building and automotive industries, according to current market trends. For automotive uses, bast fibers like hemp, kenaf, flax, etc., are chosen. However, wood plastic composite is the material of choice for the construction industry.
Due to the high level of acceptance of environmentally friendly composite materials by the automotive industry and governmental organizations and the expansion of small-scale environmentally friendly industries, it is predicted that Europe will continue to be the world's largest market for natural fiber-reinforced composites. The improvement in material performance will fuel the development of natural fiber-reinforced polymer composites in new potential fields.
Conclusion
Natural fibers are hairlike materials from natural sources (animals or plants). They are unique and distinct as they serve as renewable, sustainable, and eco-friendly materials that can be converted into non-woven and woven fabrics used mainly in textile production. A very good example is wool, which is used in producing headbands.