Materials Know How
Fundamentals of Polyethylene – Part 6: PE Performance
Don’t assume you know everything there is to know about PE because it’s been around so long. Here is yet another example of how the performance of PE is influenced by molecular weight and density.
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Fundamentals of Polyethylene – Part 5: Metallocenes
How the development of new catalysts—notably metallocenes—paved the way for the development of material grades never before possible.
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Polyethylene Fundamentals – Part 4: Failed HDPE Case Study
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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Unraveling the Science and Myth Associated With Moisture Analysis — Part 2
Once you’ve selected the right moisture analyzer, the task of method development begins. Don’t skip this step or you’ll run into problems. Here’s what happened in my lab decades ago.
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Fundamentals of Polyethylene – Part 3: Field Failures
Polyethylene 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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The Fundamentals of Polyethylene – Part 2: Density and Molecular Weight
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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The Fundamentals of Polyethylene – Part 1: The Basics
You would think we’d know all there is to know about a material that was commercialized 80 years ago. Not so for polyethylene. Let’s start by brushing up on the basics.
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Unraveling the Science and Myth Associated With Moisture Analysis— Part 1
The first task in moisture measurement is to purchase an instrument that is based on sound fundamentals. Then, before it goes into use, method development must be undertaken for all polymers that are going to be processed in the plant.
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The Fantasy and Reality of Raw Material Shelf Life: Part 2
For the vast majority of thermoplastics, the stability of the materials can be stated in years, not months. But there are exceptions where shelf life can be a serious issue.
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The Fantasy and Reality of Raw Material Shelf Life: Part 1
Is a two-year-old hygroscopic resin kept in its original packaging still useful? Let’s try to answer that question and clear up some misconceptions.
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