What Does Thermoplastic Mean?
A thermoplastic is a type of plastic made up of polymer resins that softens when heated and hardens when cooled.
Thermoplastics are easily recycled and do not show any chemical property changes when heated or cooled multiple times—which makes them easy to recycle.
When thermoplastics are heated, their physical property changes and they become a homogenized liquid and can be reshaped and re-sized. They can then be processed through methods such as injection moulding, extrusion and blow moulding.
Thermoplastic wet-end is usually encased by structural metal armor that chemical-resistant epoxy coating protects, which enables the pump to withstand hostile environments and tolerate the same loadings as metal pumps.
Corrosion accounts for about eight to 10% of the total expenditures of chemical process industries. To reduce this, engineers use corrosion-resistant plastics for process piping and storage. Thermoplastics are largely resistant to chemical attack, which makes them suitable for many process applications. These plastics are selected based on certain process specifics depending on their intended use.
Corrosionpedia Explains Thermoplastic
In harsh acidic environments—such as in cities—steel piping systems are often susceptible to rust or corrosion at the joints and therefore need special arrangements for corrosion protection. To minimize the costs associated with protecting steel pipelines that pass through severe environments, thermoplastics are considered a favorable substitute material.
Here are some thermoplastic properties making them a suitable substitute material:
- They handle corrosive materials and corrosive environments well.
- They are able to carry materials of extreme temperatures (either hot or cold); therefore they are good for just about every type of fluid transport application.
- Thermoplastic pipes usually have a small diameter, ranging from a one-quarter inch to 16 inches, and are often used for water pipes in residential and commercial buildings.
Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) are commonly used to manufacture steel pipes in harsh acidic environments. Polypropylene, polyvinylidene fluoride (PVDF), acrylonitrile butadiene styrene (ABS), nylon and polyethylene may also be used. Polyethylene gas tanks are used to transport natural gas for residential and commercial purposes.
Thermoplastics are good solutions for many uses, offering good resistance to acid and alkaline solutions. As they are characterized by their high resistance to chemical agents, and as they have extensive chemical compatibility, they are widely used in the manufacturing of industrial components. They are widely used technical materials in fields requiring the construction of pumps and mixers. However, they are not the best option for strongly oxidizing concentrated acids and for halogens.
There is a need pump chemicals at both ends of the pH range safely—and without having to be exposed to their odors or effects. Chemicals commonly attack pumps made of stainless steel and noble alloys, which are also prone to corrosion attacks, as well as metal pumps. Lining these with thermoplastic removes these negative effects.
Thermoplastic powder coatings are used for components made of all kinds of metals—such as steel, aluminum and galvanized substrates, in a fluidized bed and as well as flame spraying. They can also be used conventional electrostatic spraying processes, where a prior primer application can be avoided.
Thermoplastic powder coatings result in a thicker barrier than conventional, decorative powder coatings. That's because the closed paint layer does not allow media to penetrate or escape. In addition, thermoplastic's pore-free and smooth layer avoids the formation of biofilms.
Overall, thermoplastics are characterized by very high mechanical, chemical and UV resistance. They are insulating in nature for electrical currents and noise-absorbent.