Material Selection Made Easy with the Quadrant Triangle

Searching for the perfect thermoplastic material for your application? Look no further than Quadrant Engineering Plastic Products (EPP) Materials Triangle. We developed the Materials Triangle (as well as its corresponding free app) as a way for customers to differentiate between our vast product portfolios and locate their ideal polymer. Let’s break it down.

As seen above, the Triangle is split into two sides—amorphous and semi-crystalline. While amorphous materials (left side) have a very random structure, crystalline and semi-crystalline materials (right side) have a more ordered structure. These structures, whether random or ordered, yield certain properties that can come into play when used in different applications. Understanding the properties of each type of material will help you see the pros and cons of different thermoplastics on each side of the Triangle and select accordingly.

Amorphous materials

Amorphous materials have good dimensional stability, impact resistance, and heat resistance to hot water and steam. These materials can be autoclaved without degrading the polymer and have a glass transition (Tg) temperature, which gives them the ability to be thermoformed and bonded.

At the same time, amorphous materials tend to have less chemical resistance and are prone to cracking when exposed to certain harsh chemicals. However, this poor chemical resistance results in a better ability to bond (polymers are often solvent bonded). Amorphous materials have poor wear resistance, so for dynamic applications, semi-crystalline materials can be a much better option.

Semi-crystalline materials

Semi-crystalline perform well in dynamic applications—they provide very good stiffness, strength at temperature, low friction-COF, and excellent chemical resistance. While semi-crystalline materials do have an amorphous piece to their makeup, their more rigid, pure crystalline structure gives them a specific melting temperature that makes them very difficult to thermoform.

Understanding the differences between amorphous and semi-crystalline materials can help you select the perfect material for your application. When in doubt, check the Triangle!


Click HERE to utilize the Quadrant EPP Online Material Selection Tool

Click HERE to Download the FREE Quadrant EPP Plastics Selector App



Jesse Garcia
Application Development Engineer / South Central US Territory


TECH TALK: Minimum Service Temperature of Engineering Thermoplastic
TECH TALK:Temperature Resistance of Engineering Plastics
Phone: 610.320.6600
Fax: 610.320.6638
2120 Fairmont Avenue
Reading, PA 19612 – 4235