Breaking Tullomer fiber reported at 4x the strength of PEEK Z-POLYMERS — Lowell, Massachusetts Prints on a desktop machine, beats stainless steel 4 startups founded From Bell Labs to the hydrogen economy RPI · MIT · UPenn Breaking Tullomer fiber reported at 4x the strength of PEEK Z-POLYMERS — Lowell, Massachusetts Prints on a desktop machine, beats stainless steel 4 startups founded From Bell Labs to the hydrogen economy RPI · MIT · UPenn
Founder · Scientist · Z-Polymers

Mike Zimmerman

He spun a polymer that shrugs off chemicals, ignores heat, and outmuscles steel - then made it cheap enough to run on a hobbyist's 3D printer.

Mike Zimmerman, founder and CEO of Z-Polymers
The chemist who decided physics needed a better material. — Mike Zimmerman, Lowell, MA

Most inventors chase one breakthrough. Zimmerman keeps founding companies until the molecule behaves. Tullomer is his fourth swing - and the one printing on desktops from Lowell to the lab bench.

4
startups founded
PEEK strength (reported)
30+
years teaching at Tufts

A spool of filament that thinks it's a metal

Walk into a maker forum and you will find people arguing about a thread called Tullomer the way wine people argue about a vintage. It comes off the spool looking like ordinary plastic. It does not behave like ordinary plastic. Z-Polymers, the company Zimmerman founded in 2021, markets it as a super polymer with mechanical strength reported at more than four times that of PEEK, the engineering plastic aerospace teams already treat as premium. Reviewers on YouTube took to calling it the "unicorn filament," partly because the numbers sounded made up.

The trick is not just the chemistry. It is the process. High-performance fibers like aramids and ultra-high-molecular-weight polyethylene usually demand complex, solvent-heavy solution spinning. Zimmerman's team went a different route: direct melt-spinning, the cleaner and cheaper path. That decision is the whole thesis. A material is only revolutionary if someone can actually afford to make it, and a fiber that matches exotic performance at aramid-class pricing is the kind of thing defense and aerospace buyers notice.

Then there is the part that makes hobbyists grin: Tullomer runs on inexpensive, non-proprietary desktop printers. High chemical resistance, very low moisture absorption, non-flammable, low dielectric loss, a stable coefficient of thermal expansion - the spec sheet reads like a wishlist for parts that normally get machined out of metal. Zimmerman's bet is that you should be able to print those parts on a machine that fits on a workbench.

We identify and solve fundamental problems in mission-critical industries with polymer science. — Z-Polymers, on its mission

The applications fan out in three directions Z-Polymers cares about. Environmental: replacing toxic, less sustainable materials with recyclable ones. Safety: strong, lightweight fiber for bulletproof vests and protective gear. Medical: 3D-printed prosthetics and devices. There is an energy thread too - the company's roots reach into fuel cells and the hydrogen economy, which is no accident given where Zimmerman spent the last decade.

Because the through-line of his career is not a single product. It is a method: find a stubborn material problem inside a giant industry, then go invent the polymer that breaks the logjam. He has done it for semiconductors, for batteries, and now for fiber.

Tullomer, by the numbers it likes to brag about

Strength that exceeds stainless steel. Weight that doesn't. A melt-spinning process that skips the solvent bath. The headline claims, drawn from Z-Polymers' own materials - shown here as relative impressions, not lab certifications.

non-flammable chemical-resistant low dielectric low moisture recyclable desktop-printable
Tensile strength vs. PEEK~4×
Strength vs. stainless steelexceeds
Chemical resistancevery high
Moisture absorptionvery low
Weightlightweight
Where It Goes

One filament, every hard problem

Defense & Safety

Body armor that breathes easier

Strong, lightweight fiber aimed at bulletproof vests and protective gear - the textile end of the business that wants to reshore US manufacturing.

Aerospace & Transport

Metal-grade parts, no machine shop

Stable thermal expansion and steel-beating strength make Tullomer a candidate for lightweight structural components in aerospace, automotive and transportation.

Medical

Printed prosthetics, biocompatible fibers

3D-printed medical devices and prosthetics that lean on the material's inertness and chemical resistance.

Energy

From batteries to hydrogen

Z-Polymers traces its roots to fuel cells and the hydrogen economy - the same energy frontier Zimmerman chased at Ionic Materials.

Electronics

Low-loss at high GHz

Low dielectric properties echo Zimmerman's earlier liquid crystal polymer work for 5G and high-frequency packaging.

Makers

The "unicorn filament"

Sold through partners like Dynamism, Tullomer brought commercial-grade output to consumer-grade printers - and a cult following.

He keeps building the company instead of writing the paper

A tenured professor could have spent thirty years publishing. Zimmerman taught materials science at Tufts as a Professor of the Practice - the title says it - and kept one foot in the lab and the other in a Delaware incorporation filing. Four startups later, the pattern is unmistakable: he invents to ship, not to cite.

His solid-state battery work at Ionic Materials was compelling enough to land on a PBS NOVA documentary, "Search for the Super Battery." Z-Polymers itself grew out of fiber and filament research at UMass Lowell, incubated at the university's Innovation Hub before it had a storefront. The name is the tell - it starts with the last letter of the alphabet and the first letter of his own.

inventivepersistentindustry-bridgingpragmaticmission-driven
Replace the toxic. Outperform the expensive. Make it here. — The Z-Polymers thesis, paraphrased from its public mission
Fun Facts

Things that don't fit on a spec sheet

• Worked at two legendary research houses: Bell Labs and Saint-Gobain.
• Three engineering degrees, three famous schools, one discipline.
• Has been a visiting professor at Imperial College London.
• The company is literally named after his initial.

Watch

The internet stress-tests the unicorn

Makers love a bold claim and love disproving one even more. Here is what the 3D-printing crowd did with a spool of Tullomer.

Unicorn Filament? Tullomer from Z-Polymers!
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Compositing Tullomer from Z-Polymers
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Love it or Hate it: Tullomer filament
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Share the story

Stronger than steel, light enough for a desktop printer. Worth a forward.

Profile compiled from public sources. Performance figures reflect Z-Polymers' own marketing claims, shown as relative impressions rather than independently verified lab data.