Resins belong to the group of polymers, these materials are available from natural and synthetic sources and are found in two semi-solid and liquid forms, which have different properties and applications. Since this polymer material was used until now, it has undergone many changes. If you are curious about the structure and characteristics of resins and want to know about their scope of application, stay with us.
General characteristics of resins:
Resins are compounds made of long chains with high molecular weight. These chains have active functional groups. In fact, there is no specific criteria for general definition and giving a single format to resins, in terms of appearance characteristics such as: viscosity, color, transparency, etc., they have nothing in common with each other. But the task of all resins (adhesion, film formation, strength) is the same. Pay attention to the following examples:
1. Some coating ingredients (paint, glue, sealant, etc.) do not have the ability to create a film (thin layer) without resin, it is this resin that enables film formation.
2. Keeping parts together is one of the duties of resin. to obtain a uniform distribution, provided that the type of coating corresponds to the nature of the resin.
3. Adhesion to surfaces is one of the main functions of resins. The more the resin particles bond with the surface molecules, the higher the adhesion and, as a result, the longer the life of the coating.
4. Resins create special characteristics such as strength against chemicals (acids, alkalis, oils), temperature and resistance to corrosion, humidity, especially sea water, hot water, etc.
Types of resins:
As mentioned before, resins are divided into two categories: natural and synthetic resins:
Natural resins:
The resin of this polymer material is obtained from various sources such as: plants, insects and minerals. These resins (polymer) are easily moldable, but less durable.
Types of natural resins:
Resins of plant origin:
– Colophony or rosin: the residue of unrefined turpentine distillation of the pith, sap of the stem and root of the pine tree.
– Sandarac and lignin: from the sap of trees such as pine
– Amber is obtained as a result of the hardening and then fossilization of plant gum, which is usually yellow and in rare cases blue.
Resins of animal origin:
– Shellac (shellac), a resin that is obtained from a kind of lacquer-making insect native to India and Thailand, which is the gloss of many dragees, gums and candies from these secretions.
Resins of mineral origin:
– Copal resin and coal tar, which are obtained from coal tar and have fossil origin. Coltar is used to modify and improve the resistance and impermeability of other resins.
– Natural bitumen which can be extracted from the evaporation of crude oil or in mineral form.
In general, today natural resins do not have the past position in industries, but if needed, some natural resins such as cellulose and protein can be used by modifying and combining them with other materials.
Application of natural resins:
It is not surprising that due to the diverse chemical structure of natural resins, their applications are diverse. Antimicrobial property of these materials is the reason for using them for embalming corpses, treating continuous skin burns (radiation burns). Natural resins were also used in non-medical uses such as polishes, varnishes, waterproof materials, adhesives, and also in prefabricated materials for the production of industrial chemicals. Other uses of these materials include making jewelry, perfume, ink, etc.
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