Thermoset plastic vs Thermoplastic: What’s the difference?

Do you know what the difference is between thermosetplastic and thermoplastic? If not, don’t worry! You’re not alone. Many people are unsure of the difference between these two types of plastic. In this blog post, we will discuss the differences between thermosetplastic and thermoplastic, as well as their respective benefits and drawbacks.

Thermoplastics can be softened or fused by repeated heating to form crystals. And thermosetting plastic general process is as follows: thermosetting plastic material joining machine barrel, first by heat melt flow state, and then quickly into single or multiple under strong pressure in the cavity, the cavity in the heated to high temperatures for a period of time, this time to add a chemical crosslinking agent and curing agent, then curing hard products by open mould to retrieve. Because the product itself has been cured, so the mold does not need to be cooled, usually electric heating core constant temperature control to maintain a long time at 150 ~ 205℃.

What is thermosetplastic?

plastic molded parts

Thermosetplastic is a type of plastic that is set or cured using heat. Thermosetplastics are generally stronger and more durable than thermoplastics. However, once thermosetplastics are set, they cannot be melted down and reformed like thermoplastics can.

Thermosetting plastics can soften the flow when heated for the first time, heated to a certain temperature, resulting in a chemical reaction a crosslinking reaction and solidified hard, this change is irreversible, after that, when heated again, can no longer become soft flow. It is with this characteristic that the molding process uses the plasticizing flow during the first heating to fill the cavity under pressure and solidify into a product of defined shape and size.

Thermosetting plastic resin before curing is linear or with branched chains, after curing between the molecular chains to form chemical bonds, become a three degree network structure, not only can not remelt contact, also can not dissolve in the solvent. Phenolic, formaldehyde, melamine formaldehyde, epoxy, unsaturated polyester, organic silicon and other plastics, are thermosetting plastics.

What is thermoplastic?


Thermoplastic is a type of plastic that can be melted and reformed multiple times. Thermoplastics are generally less strong and durable than thermosetplastics. However, they can be melted down and reformed as needed, which makes them more versatile than thermosetplastics.

When heated, it becomes soft and flows, and when cooled, it becomes hard. This process is reversible and can be repeated. Polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyformaldehyde, polycarbonate cheese, polyamide, acrylic plastics, other polyene invasion and copolymer, poly (phenyl ether), chlorinated polyether and so on are thermoplastic plastics.

The resin molecular chains in thermoplastics are linear or branched chains. There is no chemical bond between the molecular chains, and the flow is softened when heated. The process of cooling and hardening is a physical change.

Difference between thermoplastics and thermosetplastics

The main difference between thermoplastics and thermosetplastics is that thermoplastics can be melted and reformed multiple times while thermosetplastics cannot. Thermoplastics are generally less strong and durable than thermosetplastics, but they are more versatile. Thermosetting plastics, on the other hand, are stronger and more durable, but once they are set, they cannot be melted down and reformed.

Thermoplastics are made from linear or branched chains of molecules, while thermosetting plastics are made from cross-linked chains of molecules. Thermoplastics can be softened by heat and reformed into different shapes. Thermosetplastics, on the other hand, are set or cured using heat and cannot be melted down or reformed once they have been set. Thermoplastics are generally less strong and durable than thermosetplastics, but they are more versatile. Thermosetting plastics, on the other hand, are stronger and more durable but cannot be melted down or reformed once they have been set.

FEATURES Thermoplast Thermoset
Molecular structure Linear polymer; Weak molecular bonds in straight chain form Network polymer; High degree of crosslinking and strengthening molecular bonds
Melting Point The melting point is lower than the degradation temperature The melting point is higher than the degradation temperature
Mechanical property Flexible and elastic, high impact resistance (10 times higher than thermosetting plastics). Strength comes from crystallization Inelastic and fragile, strong and rigid, strength from crosslinking
Microstructure It is composed of solid hard crystals and elastic amorphous regions It is composed of solid thermosetting resins and reinforcing fibers
Size Size is expressed in molecular weight Size is expressed in terms of cross-linking density
Retrievability Recycled by heating and/or pressurization Unrecyclable
Chemical resistance Highly resistant to chemical corrosion Heat and chemical resistance
Crack Repair The cracks can be repaired easily Difficult to repair crack
  • List of thermosetting materials:

– Phenolic

– Formaldehyde

– Melamine formaldehyde

– Epoxy

– unsaturated polyester

– Organic silicon, etc.


  • Application:

Thermosetting plastics mainly used for pressing, extrusion and injection molding. Silicone, epoxy resins and other plastics, mainly used as low pressure extrusion sealing electronic components, and casting forming.

  • List of thermoplastic materials:

– Polyethylene (PE)

– Polypropylene (PP)

– Polyvinyl chloride (PVC)

– Polystyrene (PS)

– Polyformaldehyde (POM)

– Polycarbonate (PC)

– Cheese polyamide (PA), etc.

  • Application:

Thermoplastics are used in a variety of applications, including food packaging, medical devices and car parts. Thermoplastics are also used to make toys, bottles and other consumer products.

Their Advantages & Disadvantages

Thermoset Plastic Vs Thermoplastic

Advantages of Thermosetting Plastics:

  • They have a high molecular weight. This gives them a high degree of crosslinking, which makes them stronger and more durable.
  • They are resistant to heat and chemicals.
  • They have a long life span.

Disadvantages of Thermosetting Plastics:

  • They cannot be melted down and reformed. Once they are set, they remain in that state.
  • They are not as versatile as thermoplastics.

Advantages of Thermoplastics:

  • They can be melted down and reformed as needed, which makes them more versatile than thermosetplastics.
  • They are lighter and easier to work with than thermosetplastics.
  • They have a shorter life span than thermosetplastics but are still more durable than most other materials.

Disadvantages of Thermoplastics:

  • They are not as strong or durable as thermosetplastics.
  • They can be damaged by heat and chemicals.


Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.