Molecular Weight, What is it and what does it have to do with Body Armor?

Molecular Weight, What is it and what does it have to do with Body Armor?

Molecular Weight | What is it, and What Does it Have to do With Body Armor?

What do we mean by ultra-high-molecular-weight-polyethylene? We’ve already written about polyethylene in extensive detail, so today, we’re going to break down molecular weight and why it’s so important for the plates worn in your tactical vest.

What Is Molecular Weight?

Molecular weight is also known as something called molecular mass. It has to do with the weight of an atom. If you remember back in school when they talked about how tiny particles are, did you ever think about how you’d weigh something so small?

Probably not, but it’s still an important consideration to make. Why? Because the more dense something is, the more potential for durability, it has. And when considering molecular weight for body armor, particularly polyethylene produced armor, the weight is minimal with highly-rated bullet-resistant material.

Whatever it is, the way you tell your story online can make all the difference.

Whatever it is, the way you tell your story online can make all the difference.

Just to give you an idea of molecular weight, here are a few average weights of things you might recognize. Let’s start with air; air has a molecular weight of 28.966 kg/kmol. Ethyl alcohol has a molecular weight of 46.07 kg/kmol. Even oxygen can be weighed; oxygen has a molecular weight of 31.9988 kg/kmol. 

Basically, all the things you thought couldn’t be weighed can, and that includes the polyethylene in UHMWP. And if we’re listing things in molecular weight, it’s going to be light, and nothing is more lightweight than ShotStop®!


Why does molecular weight matter when it comes to body armor? Well, if you’ve ever worn a tactical vest with plate inserts, you know that weight is everything. The less weight you have to carry around, the longer you can perform your duties without inhibiting your abilities.

Whatever it is, the way you tell your story online can make all the difference.

Whatever it is, the way you tell your story online can make all the difference.

Therefore, you want materials that are so lightweight that you’re getting weights listed in molecular measurements, not pounds. That’s because if you start with pounds, you can go ahead and assume you’re going to end up with a much heavier product. You’re going to end up lugging around pounds that turn into pain, and nobody wants that.

Ultra-High-Molecular-Weight-Polyethylene (UHMWPE)

So, where does molecular weight fit into the big picture of ballistic wear? As you might have already seen, we’ve written a few in-depth blogs on UHMWPE, so we won’t bore you by repeating old content. However, it’s still worth a quick review, particularly to those of you who haven’t read our blog, Polyethylene, and Body Armor. So, before getting too deep into things like gel-spinning and other fancy terms needed to explain the process of manufacturing body armor, let’s review.


UHMWPE is used to create lightweight ballistic protection that’s as strong in tensile strength as it’s light in weight. Made from a polymer, like your lightweight holster, this UHMWPE is much stronger because of gel-spinning that causes the molecules to become tightly packed together.

It works as a material for body armor because it absorbs (transfers) kinetic energy very efficiently, and it’s a lightweight, low-profile option.


Now that our mini-review is over let’s get into gel-spinning, which is pretty cool if you ask us. 

Gel-spinning creates these tightly packed molecules to help reinforce fiber. This process is sometimes known as semi-melt spinning. No matter what you call it, this method of producing body armor creates high-strength and high-mechanical-property fibers. These are prepared in a gel state (one might assume this is where the gel makes its way into the title) to get high-elastic fiber modules.

During gel spinning, the extrusion of polymer solution, also known as plasticized gel from spinnerets, occurs. Once that happens, the polymer solution is cooled in some type of solvent or even water. After the cooling, the solution can now be stretched into gel fibers. 

The entire process is known as an ultra-high extension– that’s where the Ultra-High of UHMWPE comes from, in case you were wondering.


Since gel-spinning helps create UHMWPE, one might conclude that it’s vital to molecular weight–it’s in the name, after all. And if you’ve come to that conclusion, you are correct because gel spinning promotes the polymer fiber’s molecular weight. 

Of course, that’s not all it enables, as we use it for the degree of orientation, crystallinity, and the effectiveness of fiber density. While we won’t be going into each of these in this article, you should know that each is needed to give this fiber the strength it requires for use as ballistic protection.

ShotStop® UHMWPE Ballistic Plates

If you want the thinnest, lightest, most advanced body armor on the market, our UHMWPE plates have it all; all but the extra weight found in heavier plates, such as those made with steel.

Let’s take a look at our PA plate, for instance. Our Duritium® PA plate is 100% polyethylene. It’s made from our own Duritium® polyethylene, ultra molecular weight, high-density polyethylene, and we call it our Ferrari plate.

Whatever it is, the way you tell your story online can make all the difference.

Whatever it is, the way you tell your story online can make all the difference.

What’s so great about this particular plate? 

“It’s currently the world’s thinnest and lightest level 3 plate currently listed on NIJ’s compliant products list. With that, we’re coming in at about .7 inches thick. It weighs under 3 pounds, and it does have very strong multi-hit capabilities.”

-Jason Henkel, Director of ShotStop® Operations

So, if you’re looking for the best technology utilization with maximum mobility and survivability, then this very thin, lightweight, and extremely strong ballistic plate is for you!


Are you interested in learning about the materials ShotStop® uses in its UHMWPE body armor? Read our blogs: Polyethylene and Body Armor and What is Duritium® Technology? And as always, don’t hesitate to reach out about getting your unit in the lightest, thinnest, and most comfortable ballistic plates on the market. 

Email us at with any questions.

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