MATERIALS KNOW HOW

Tracing the History of Polymeric Materials, Part 28: Making LCP's Melt Processable

Liquid-crystal polymers based on a single monomer produces a polymer with a very high melting point.This presents two problems. Here’s how they were solved.

The Effects of Time on Polymers

The Effects of Time on Polymers

Last month we briefly discussed the influence of temperature on the mechanical properties of polymers and reviewed some of the structural considerations that govern these effects.
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The Effects of Stress on Polymers

Previously we have discussed the effects of temperature and time on the long-term behavior of polymers. Now let's take a look at stress.
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Tracing the History of Polymeric Materials, Part 27: Liquid-Crystal Polymers

Liquid-crystal polymers debuted in the mid-1980s, but the history of the chemistry associated with this class of materials actually starts a century earlier.  

Tracing the History of Polymeric Materials, Part 26: High-Performance Thermoplastics

The majority of the polymers that today we rely on for outstanding performance — such as polysulfone, polyethersulfone, polyphenylsulfone and PPS — were introduced in the period between 1965 and 1985. Here’s how they entered your toolbox of engineering of materials.    

Tracing the History of Polymeric Materials, Part 25: Silicones

The long road to the development of silicone resulted in a chemistry that is remarkably versatile.  

The Importance of Melt & Mold Temperature

Molders should realize how significantly process conditions can influence the final properties of the part.
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Tracing the History of Polymeric Materials: Silicones

More properly known as siloxanes, silicones are a class of materials where no carbon is present in the polymer backbone.  

How Do You Like Your Acetal: Homopolymer or Copolymer?

Acetal materials have been a commercial option for more than 50 years.

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.

The Strain Rate Effect

The rate of loading for a plastic material is a key component of how we perceive its performance. 

Why (and What) You Need to Dry

Other than polyolefins, almost every other polymer exhibits some level of polarity and therefore can absorb a certain amount of moisture from the atmosphere. Here’s a look at some of these materials, and what needs to be done to dry them.
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Tracing the History of Polymeric Materials: The Commercialization of Acrylic

We covered the invention of acrylic in our last installment. Here, we discuss its commercial development.  

Melt Flow Rate Testing–Part 1

Though often criticized, MFR is a very good gauge of the relative average molecular weight of the polymer. Since molecular weight (MW) is the driving force behind performance in polymers, it turns out to be a very useful number.

Tracing the History of Polymeric Materials: Acrylic

How acrylic was born.  

The Effects of Temperature

The polymers we work with follow the same principles as the body: the hotter the environment becomes, the less performance we can expect.

Understanding Strain-Rate Sensitivity In Polymers

Material behavior is fundamentally determined by the equivalence of time and temperature. But that principle tends to be lost on processors and designers. Here’s some guidance.
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Density & Molecular Weight in Polyethylene

This so-called 'commodity' material is actually quite complex, making selecting the right type a challenge.
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Tracing the History of Polymeric Materials: Aliphatic Polyketone

Aliphatic polyketone is a material that gets little attention but is similar in chemistry to nylons, polyesters and acetals.    

Tracing the History of Polymeric Materials: Acetal

The road from discovery in the lab to commercial viability can be long, and this was certainly the case for acetal polymers.  

Tracing the History of Polymeric Materials: The Differences Between Nylons & Polyesters

In many respects, nylons and polyesters appear to be interchangeable. But there are interesting differences in the properties of these two families that arise from their chemical structures.  

Tracing the History of Polymeric Materials: Polyesters

Beyond PET, PBT and their analogues, development of polyester chemistry led to unsaturated thermosetting resins, copolyester thermoplastic elastomers, liquid-crystal polymers and, most recently, biopolymers.