The main difference between plasticizer and retarder is that plasticizer is a chemical that is added to materials to increase their flexibility, plasticity, durability, and workability, whereas retarder is added to materials to slow down the setting or hardening of the material.
Plasticizers and retarders are chemicals useful in various industries, including the construction and polymer manufacturing industries. These two chemicals are types of chemical additives.
Key Areas Covered
1. What is a Plasticizer
– Definition, Mechanism of Action, Uses
2. What is a Retarder
– Definition, Mechanism of Action, Uses
3. Difference Between Plasticizer and Retarder
– Comparison of Key Differences
What is a Plasticizer
A plasticizer is a substance added to the materials to make the substance softer and increase its plasticity, flexibility, durability, and workability. Plasticizers also decrease the viscosity of the substance and decrease the friction during its handling in manufacture. Hence, it is a type of additive. Some plasticizers are more efficient than others. The efficiency of a plasticizer is about making the product softer. Plasticizers work by reducing the intermolecular forces between polymer chains, which increases the distance between them and allows them to move more freely.
Plasticizers are colorless and odorless esters, mainly phthalates. A reaction of an alcohol with an acid like phthalic anhydride and adipic acid produces plasticizers. The selection of alcohol and acid determines the type of ester (hence the type of plasticizer). Esters thus produced have a large variety. But only some of the esters have the right standards in terms of availability, health, performance, and environmental requirements required by the market.
Plasticizers are used in the production of polyvinyl chloride, which is flexible. Some plasticizers are also helpful in the production of rubber, paints, sealants, adhesives, and in printing links. However, certain plasticizers exhibit toxic nature. In fact, some low molecular weight ortho-phthalates are potential endocrine disruptors.
What is a Retarder
A retarder is a chemical added to the materials to slow down the setting or the hardening of a material. Retarders are very useful in the production of concrete. Another name for concrete retarders is retarding admixtures. The setting time of the concrete mixture is delayed by one hour when a retarder is added. Apart from slowing down the process, retarder also saves water.
Retarders work either by reacting with the setting agents in the material or by interfering with the chemical reaction itself. The mechanism of retardation includes the steps of adsorption, nucleation, complexation, and precipitation. Moreover, we can classify concrete retarders into two types: organic retarders and inorganic retarders. Organic retarders include starches, cellulose, products phosphonates and their sugars, lignosulphonates and their sugars, hydroxycarboxylic acids, and their salts, while inorganic retarders include salts of Pb, Zn, Cu, As and Sb, borates, and phosphonates.
Retarders in Concrete
Retarders have various effects on concrete, such as strength, practicality, slump loss, volume distortion, and durability. Furthermore, the most common type of concrete retarders is calcium sulfate-gypsum and sugar. The retarding admixtures preserve the workability and cohesion of concrete. They also lengthen the time takes for it to set. Hence these retarding admixtures enhance the permeability. Concrete retarders are useful in lessening the amount of segregation and bleeding when poor sand grading is unavoidable. Retarders are commonly in use when building huge constructions. They are also useful during the grouting process for oil wells.
There are disadvantages to using retarders too. Though gypsum delays concrete setting, the addition of too much gypsum leads to undesirable expansion and endless delay when setting the concrete.
Hence, extensive use of retarders can lead to extended setting times. Retarders can sometimes reduce the early strength of concrete. Another disadvantage of retarders is that it increases the cost of concrete, and it also has an increased risk of cracking.
Difference Between Plasticizer and Retarder
A plasticizer is a chemical that is added to materials to increase their flexibility, plasticity, durability, and workability, whereas a retarder is added to materials to slow down the setting or hardening of the material.
Mechanism of Action
Plasticizers work by reducing the intermolecular forces between polymer chains, which increases the distance between them and allows them to move more freely. Retarders, on the other hand, work either by reacting with the setting agents in the material or by interfering with the chemical reaction itself.
Moreover, plasticizers are used in the production of polyvinyl chloride, rubber, paints, sealants, adhesives, and in printing inks, while retarders are used in concrete, huge construction, and used during grouting process for oil wells.
Certain plasticizers exhibit toxic nature, and some may be potential endocrine disruptors. However, retarders increase the cost of concrete, reduce the early strength, and, if used in larger quantities, delay the concrete’s setting.
Plasticizers and retarders are two different chemicals that have different uses and act as additives. The main difference between plasticizer and retarder is that a plasticizer is a chemical we add to materials to increase their flexibility, plasticity, durability, and workability, whereas a retarder is a chemical we add to materials to slow down the setting or hardening of the material.
1. “Plasticizer – Overview.” Science Direct.
2. “Retarders for Concrete – Mechanisms, Types and Effects on Properties.” The Constructor.