Bandaging materials are made from fibres of various origins. Initially, fibres came primarily from natural sources, but developments in technology have resulted in the addition of semi-synthetic and synthetic fibres. These fibres are bound together to create a fabric. One of the oldest binding techniques is achieved by spinning fibres into threads which are subsequently woven together. The weave structure and the kind of fibres used determine the specific characteristics of the fabric.
Nowadays, bandaging products are increasingly manufactured using the non-woven technique. Non-woven means that the threads are bound together in a different way, other than weaving. This can be by heating the fibres, after which they adhere to a membrane, by compressing wet fibres together or by using chemical or synthetic bonding agents. This non-woven technique is not only used to bind chemical cellulose fibres to a membrane, but natural fibres can also be processed in this way. For specific applications, agents can be added to the bandaging tissue, such as plaster of Paris or resin for plaster casts, adhesive products, disinfectants, drugs etc.
Natural Fibres
Natural fibres are derived from animal or vegetable sources. The most commonly used fibres are cotton, linen, cellulose and rubber.
Cotton is the fluff that surrounds the seeds in the cotton plant seed boll. When the fruit is ripe, the seed boll opens and the fluff bursts out. Each seed strand is about as thick as a human hair and about 2 to 5 cm long. This cotton fibre consists mainly of cellulose. While the fibre is still in the seed boll, it forms a fine fluid-filled tube. Once the cotton has been picked, this fluid evaporates and the fibre winds around its axis, forming a spiral. This spiral shape makes it easy to spin the fibres into a tight thread. Each fibre is coated with a wax-like substance, called cuticle. This waxy layer is fairly impermeable to water, making cotton naturally water-resistant. After removal of this waxy layer, the cotton optimally absorbs moisture due to the cellulose and the space within the fibre. Purified cotton is a good heat conductor, as a result of which it feels cool and does not insulate.
Linen is manufactured from the bast fibres of the flax plant. Linen absorbs moisture more rapidly than cotton but, up to about 20% humidity, does not feel wet. Linen is also stronger than cotton, but is rigid and non-elastic.
Cellulose is derived from wood. After the wood has been crushed, the structure of the wood fibres is broken down with calcium sulphite treatment. The cellulose pulp is then purified, bleached and dried. The woolly cellulose fibres resulting from this process have a high absorption capacity, but are not suitable for spinning into threads. The fibres are usually bound together chemically or mechanically to produce a textile-like material.
After processing, natural rubber is suitable for processing into bandaging materials which require elasticity. The rough surface of the material has an anti-slip effect, as a result of which the bandage layers are less likely to move about. Rubber is also used in the adhesive component of plasters.
Semi-Synthetic Fibres
Semi-synthetic fibres are made using less pure cellulose from pine wood. After the wood has been subjected to chemical treatment, a pulp, known as viscose, is obtained. This pulp is extruded into filaments. The viscose material obtained is a rod-like fibre with lengthwise indentations. Although viscose has a lower absorption capacity than cotton, it does have a higher rate of absorption and is a fairly good heat conductor.
Synthetic Fibres
A few important groups of chemically prepared polymers used to produce synthetic fibres include: polyamides (nylon), polyesters (acrylic), polyvinyl chloride (PVC) and polyurethane (PU). The composition and smooth surface of the fibres means they do not absorb moisture, but allow it to rapidly leak away through the fabric. Synthetic fibres are generally strong and elastic. The use of synthetic fibres has greatly increased the range of bandaging products available. It is often easier to adapt these materials to the range of requirements for specific bandaging materials, for example by combining certain synthetic fibres with each other or with natural fibres in the weave structure. Synthetic fibres are also often used in the carrier material for the adhesive in elastoplasts.