Meet the Team

Meet the Team: Nathan Enser, Polymer Chemist


When Nathan Enser started at Apple Rubber as an undergraduate intern, he was a chemical engineering major at the University at Buffalo. His experiences at Apple Rubber, however, stoked his interest in — and led him to change his major to — biomedical engineering.

Now a polymer chemist, Enser’s job entails customizing existing “recipes” to meet customer specifications for compounds.

Tell us about Apple’s ability to provide custom compounds.

Nathan Enser: We have a decent library of custom materials — they may fit or be a good starting point for a large variety of roles. So far this year, I’ve added maybe two new compounds to our library.

To get started on a customer’s job, we first see what the specifications are. We rarely have to start from scratch. There’s a lot of good information out there, so we basically reformulate the compound by changing the levels of ingredients. I’ll get the formula from my boss, then mix and test it. We make sure we are getting the info right, and see what works.

What types of things do customers specify?

NE: Changing pigment—that’s easy to do, as long as it’s a basic color. Medical companies are more likely to be looking for a pastel, and for that you have to use a blend of pigments. Compounds with blended pigments can be more difficult to run through moving parts — the silicone can split. (Ed. note – for more info on this topic, check out Nathan’s Hot Topics blog post, “The Effects of Pigment on Medical Silicone)

If a customer wants to overcome an issue like friction, say, with a dynamic seal, we might add something to remedy that. Rubber, for instance, doesn’t like having certain chemicals inside the compound, so that will come to the surface and create a slippery coating. We’re not really altering the property, but adding something to affect the surface interaction.

What kind of testing do you do on the materials?

NE: Normally we are trying to meet aerospace, military, or automotive specs. I’ll get a written set of requirements in terms of its resistance to elements like fuel and oil styles, temperature, or aging. We’ll intentionally age the rubber to see how it holds up, put it under high and low heat conditions, and soak in it oil or fuel to see how it holds up. Based on those results, we might tweak it.

In nitrile rubber compounds, the acrylonitrile content or ACN percentage is a large component that determines a material’s fuel and oil resistance. The higher the number, the more resistant it will be. However, if we up the ACN percentage, it can then have other effects, like how effective the compound will be at different temperatures – we are always seeking a balance.

Why did you think that biomedical engineering would be a good fit for you?

I enjoyed chemistry as kid, so I thought, “Why not mix chemistry and physics?” I’ve been at Apple Rubber for about 10 years now.

What do you do in your free time?

On and off, since I was a kid, I’ve had salt-water/coral reef tanks. I got more into them after college —  I didn’t have to spend time studying for school any more, so I decided to put my time into researching salt-water fish.

What do you like about it?

First of all, you can design an environment and balance all your conditions. I approach it like an engineering problem. I design my tank with as much automated functionality as possible, and a random water flow pattern. I also have large polyp stony coral, they are fluid and in motion.

What is the end result?

It’s really peaceful — a constantly changing pattern to sit and watch. The different fish species each have their own little personality — some watch what’s going on in the room, some of them, like the sand-shifters, are just entertaining.

Thanks for your time, Nathan!