KNOW-HOW - MATERIALS

Materials Know How

PBT and PET Polyester: The Difference Crystallinity Makes

To properly understand the differences in performance between PET and PBT we need to compare apples to apples—the semi-crystalline forms of each polymer.

Commodity Resins

Part 5 of 6: Fundamentals of Polyethylene

How the development of new catalysts—notably metallocenes—paved the way for the development of material grades never before possible.
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Commodity Resins

Part 4 of 6: Polyethylene Fundamentals

Injection molders of small fuel tanks learned the hard way that a very small difference in density—0.6%—could make a large difference in PE stress-crack resistance.
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Materials Know How

Part 3 of 6: Fundamentals of Polyethylene

PE parts can fail when an inappropriate density is selected. Let’s look at some examples and examine what happened and why.
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Commodity Resins

Part 2 of 6: The Fundamentals of Polyethylene

PE properties can be adjusted either by changing the molecular weight or by altering the density. While this increases the possible combinations of properties, it also requires that the specification for the material be precise.
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Commodity Resins

Part 1 of 6: The Fundamentals of Polyethylene

You would think we’d know all there is to know about a material that was commercialized 80 years ago. Not so for PE. Let’s start by brushing up on the basics.
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Materials Know How

PART 2: The Importance of Mold Temperature When Processing Polycarbonate

Don’t be afraid to increase mold temperature to improve part quality when making PC parts. Take a look at a few examples here.

Materials Know How

Part 1: The Importance of Mold Temperature When Processing Polycarbonate

An often overlooked factor in optimizing the ductility of PC is the rate at which the polymer is cooled in the mold.

Materials Know How

Part 5: Heat Deflection Temperature vs. Dynamic Mechanical Analysis

In the final part of this five-installment series, we bring DMA to a practical level using the results for glass-filled nylon.
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Testing

Part 4: Heat Deflection Temperature vs. Dynamic Mechanical Analysis

The presentation of DMA data can sometimes frustrate users and discourage its adoption. Those unfamiliar with DMA should insist on receiving data relevant to the manner in which the part they are developing will be used.
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