Polyethylene gas tanks are used to transport natural gas for use in residential and commercial applications. Other common applications for thermoplastics include high-pressure polyethylene to encapsulate rigid objects like electrical equipment. Low-pressure polyethylene is very elastic and ideal for insulating electrical cables. Polyamide is most commonly associated with the production of ropes and belts. The primary advantage of thermoplastics is their wide range of applications.
Thermoplastics are high strength, lightweight materials and have relatively low processing costs. Additionally, thermoplastic components are relatively easy to manufacture with high volume and precision. The primary disadvantage of using thermoplastics instead of materials such as metal is their relatively low melting point. Certain types of low-quality thermoplastics can melt when they're exposed to the sun for extended periods.
Furthermore, thermoplastics can have poor resistance to organic solvents, hydrocarbons, and highly polar solvents. Thermoplastics are susceptible to creep, which occurs when the material stretches and weakens under exposure to long-term stress loads. The susceptibility to creep is further exacerbated by the lower melting temperature of the material. Other types of thermoplastics, such as composites, can fracture instead of becoming deformed under high-stress conditions. Types of thermoplastics commonly employed for manufacturing include polyethylene PE , polyvinyl chloride PVC and polystyrene PS , which often is used for packaging.
Other groups of thermoplastics are acrylics, fluoropolymers, polyesters, polyimides, and nylons. All of these types can be melted down repeatedly and re-shaped into different forms. For example, a foam cup is a thermoplastic material man be re-melted and fabricated into a dish. Thermosets and thermoplastics come in a wide range of material options and can serve different applications as long as the limitations of the material are not likely to cause product failure under the intended operating conditions.
The basic features of these materials remain the same: high versatility and recyclability. When it comes to useful applications in the real world, you would be hard-pressed to find a better example than the production of plastics through these two processes. Guides Share:. Introduction— Thermoset vs Thermoplastic The primary difference between the two is that Thermoset is a material that strengthens when heated, but cannot be remolded or heated after the initial forming, while thermoplastics can be reheated, remolded, and cooled as necessary without causing any chemical changes.
What are Thermoset Plastics? It is formed by the addition of polymerization. Thermosetting Plastic is formed by condensation polymerization. This is not expensive comparatively Thermoplastic. But Here thermosetting plastic, plasticity does not increase with temperature. It is processed by Injection molding. Thermosetting plastic is processed by Compression molding.
Plaskon is another example of thermosetting Plastics. As thermoplastics are capable of withstanding corrosive conditions, they work well as a substitute for metals, but cannot withstand high temperatures as well as thermosets. Offering an excellent combination of chemical resistance, structural robustness and thermal stability, thermosetting polymers are widely used throughout a range of industries, as they offer an economical means to meet many production specifications.
They are easily formed into complex geometric shapes that fabrication of metal components cannot easily achieve, and components made via RIM and RTM techniques allow for considerable consistency in the fabrication process. Sectors that use thermosetting polymers include the adhesive and sealant, aerospace and defense, appliance and electrical, automotive, energy, and construction industries. Understanding the difference between thermoplastic and thermoset plastics is essential for both manufacturers and product designers alike.
This drastic increase in molecular weight causes major changes in material properties, such as an increased melting point.
With a continuous increase in molecular weight due to crosslinking, the melting point can rise and reach a point that exceeds the decomposition point. In that case, a thermoset polymer would have a very high molecular weight that it would decompose before it can melt, which defines why thermoset processing is irreversible [2].
Thermoplastics generally provide high strength, flexibility and are resistant to shrinkage, depending on the type of resin the polymer in melted liquid form. They are versatile materials that can be used for anything from plastic carrier bags to high-stress bearings and precision mechanical parts. Thermosets generally yield higher chemical and heat resistance, as well as a stronger structure that does not deform easily.
Here is a list showing the difference between thermoplastics and thermosets in terms of features and properties. Notice the effect of crosslinking as an underlying factor in diverting those materials from one another. Flexible and elastic. High resistance to impact 10x more than thermosets.
Strength comes from crystallinity. Thermoplastics can be processed in a variety of methods including extrusion moulding, injection moulding, thermoforming and vacuum forming. Granular material is fed into the mould, usually in the form of spherical granules of approximately 3 mm diameter.
These granules are then heated to melting point, which requires very high temperatures. As thermoplastics are highly efficient thermal insulators, cooling during the curing process takes longer than other plastics.
Therefore, rapid cooling is undertaken to achieve a high output rate, usually by spraying with cold water or plunging into water baths. To cool thermoplastic plastic films, cold air is blown onto the surface. The plastic shrinks upon cooling, varying between a shrinkage rate of 0. The rate of cooling and shrinkage has a distinct effect on the crystallisation of the material and internal structure, which is why the shrinkage rate is always specified for thermoplastics.
Companies involved in producing thermoplastic materials include:. Thermosetting resins are processed in their liquid form under heat. The curing process involves adding curing agents, inhibitors, hardeners or plasticisers to the resin and reinforcement or fillers, depending on the required outcome.
Companies involved in producing thermosetting polymer materials include:. Thermosetting polymer composites are made using a laminating process, which binds together resins such as epoxy, silicone, melamine, etc.
Prior to curing, the reinforcement substrate is dipped into the resin binder in its liquified form. Once bound, the sheets of material are passed through an oven to partially cure them. Several sheets are then piled to the required thickness, heated and pressed together to form a laminate. Alternatively, the sheets may be wrapped together and heated to create rods.
Companies involved in producing thermosetting polymer matrix composites include:. Polyamide nylon. Tough and relatively hard material used for power tool casings, curtain rails, bearings, gear components and clothes. Stiff, durable and hard plastic that polishes to a sheen, used for signage, aircraft fuselage, windows, bathroom sinks and bathtubs. Polyvinyl Chloride PVC. Tough and durable material that is commonly used for pipes, flooring, cabinets, toys and general household and industrial fittings.
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