Blog about plastics, materials, processing and engineering tools

First of all: what is thermoplastic?

As you can find in every encyclopedia thermoplastics are materials that soften or melt when heated and harden when cooled. This is the simplest explanation ever.

This is a blog about plastics and I focus on thermoplastic polymers. Our thermoplastic polymer of course contains long polymer molecules but they are not linked to each other. They have no cross-links, and curing process is reversible because no chemical bonding takes place.

Thermoplastic resin can be purchased in granules and then heated by using molding or extrusion process to obtain the desired product.

Thermoplastics are a big family and we can find there polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, acrylics, and nylons.

Thermoset materials

In the title I mentioned thermoset materials, which can be also a polymer. The main difference is that they have cross-links between the polymers chain.


Cross-links are the results of a cross-linking reaction or a curing reaction where it is used a cross-linking agent. Cross-links are an irreversible chemical bond. This means that once the reaction finishes, the shape of the plastic/polymer part cannot be changed.


Both materials have different features. Let’s start with thermoplastics.

As it can be melt and cooled again and again, it allows to be remolded and recycled without negative effects on the physical properties.

Most materials have high strength, high-impact resistance, chemical resistant and shrink-resistance. It is eco-friendly manufactured because it can be reused or recycled.

But thermoplastics are also generally more expensive than thermoset and can be melt if heated.

How is it with thermoset resins?

Cross-links improve the mechanical properties, providing a better chemical and heat resistance.

They have a flexible design and high levels of dimensional stability, this means that the product can go from thick to thin. And the most important, it is cheap.

The disadvantage of thermoset materials is that they cannot be recycled, remolded or reshaped.

Simple, isn’t it?