Thermoplastic vs Thermoset

We are going to take a closer look at the science behind the difference between Thermoplastic elastomers and Thermoset rubbers.

Thermoset comparison

Thermoplastics and thermosets sound alike but in fact, have very different properties and characteristics. They are ideal materials for different applications. Understanding what sets them apart starts with understanding chemistry and processing. This knowledge will help you make an informed sourcing decision and ultimately select a material that will improve your product.

Thermoplastic elastomers (TPEs) can be repeatedly melted and cooled. Throughout this process, the elastomer becomes liquid at a certain temperature level but retains its shape when allowed to cool.  Thermoplastic elastomers are soluble in particular solvents and will burn if heated above a certain temperature. Care must be taken during processing and molding to avoid degradation and ignition of material, but the advantage of TPEs over thermoset rubbers is that TPE material can be continually reused.

Thermoplastic elastomer molecular chains are best compared to spaghetti.  When cooked, the spaghetti noodles soften and interweave themselves together; you can imagine a handful of noodles falling through your fingers after they have been heated in boiling water.  Then, when allowed to cool, they stay interwoven and hold their form and shape tightly.   Similarly, the molecular chains of TPEs become soft and slippery when heated, reaching more of a liquid stage and allowing the material to flow easily. At this stage, they can be molded into just about any shape and size; once cooled, they will maintain that shape.  Additionally TPEs, once cooled, can be repeatedly stretched and then will regain their shape.  TPEs, in essence, go through a physical change when being processed.

Thermoset rubbers, on the other hand, can be likened to cake.  Once the ingredients are mixed and baked, they hold a particular shape, but the finished cake cannot be poured into another pan and reshaped after it is cooked.  In a similar way, when thermoset elastomer material is processed, it goes through a curing or vulcanization process, where the molecules cross-link, causing them to be permanently insoluble and infusible and affecting many characteristics and physical properties.  Thermoset rubbers cannot be repeatedly melted and cooled, because, unlike TPEs, Thermoset rubbers go through a chemical change during processing.  This chemical change translates into more waste and the inability to reuse, remold or recycle the material. Common thermoset rubbers include neoprene, nitrile, rubber latex, silicone, and butyl.

Compared to thermoset rubbers, TPEs offer numerous advantages:

  • Recyclable and more environmentally friendly
  • Shorter processing time and lower production costs
  • Simpler processing
  • Greater design flexibility
  • Broader range of physical properties
  • Tighter control of product quality which increase the consistency of the end product

Thermoplastic Process

Thermoplastic pellets become more fluid and soften as more heat is applied. There is no chemical bonding during the process; therefore, can be reversed and the material can be remolded or reshaped as needed without affecting the quality. This allows for use of waste and scraps.

Features and Benefits

Thermoplastics can be molded into very small detailed parts. They are also capable of retaining intricate surface designs. They have a wide performance offering but commonly have high strength, are shrink resistant, and can be used in both low and high-stress parts.

Pros

  • Recyclable
  • Excellent impact resistance
  • Capable of being remolded/shaped
  • Superior aesthetic finishes
  • Thick to thin wall parts
  • Chemical resistant

Cons

  • Can melt if heated above melt point

Thermoset Process

During the curing process, thermoset polymers create chemical bonds called cross-linking. This cross-linking is not reversible and products will resist melting when heat is applied.  The natural resistance to heat makes thermosets ideal for high-heat applications in appliances and electronics.

Features and Benefits

Thermosets have a high heat resistance and structural integrity. They are used in high heat applications to avoid deformation.

Pros

  • Resistant to higher temperatures
  • Excellent aesthetic appeal
  • Flexible design
  • High level of dimensional stability
  • Thick to thin wall design

Cons

  • Not recyclable
  • Cannot be remolded or shaped
  • More scrap or waste from processing
  • Difficult to surface finish

 

Star Thermoplastics offers a wide range of thermoplastic elastomers (TPEs).  These products can be selected for particular applications as well as being created for specific functionalization. We take pride in considering your characteristic needs and helping you select a TPE that is optimal for your applications.  You can start the process by reviewing our product lines or by calling (708) 343-1100 and speaking with a product specialist today. We are here to solve your material problems.

Where do you find TPE materials?

The question, “Where do you find TPE materials?” can take a while to answer since thermoplastic elastomers are part of just about every industry in some form and to some degree.  This family of polymers first gained a foothold as a replacement for rubber, but manufacturers are just tapping into the potential advantages of incorporating thermoplastic elastomers into product designs, and the list of where TPE polymers are used grows daily.

Contact Star Thermoplastics Today!

Or call 708.343.1100

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