157 Liz Bui of Yulex: safer, sustainable materials

May 10, 2025

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Liz Bui takes us behind the scenes at Yulex, a material science company that’s replacing extremely useful, but problematic petroleum-based products with natural rubber alternatives.

Liz Bui is Chief Executive Officer at YULEX, based in the USA. She began her career in the biotechnology and pharmaceutical industry where she spent 20 years in senior roles. On top of managing all operational and business matters at YULEX, Liz is an intellectual property and transactional lawyer, a PhD scientist and also an adjunct professor at the University of San Diego School of Law.

Originally from Vietnam, at the age of six Liz escaped on the day Saigon (now Ho Chi Minh City) fell to the North Vietnamese forces. She and her siblings, without their parents, were war refugees aboard a fishing boat until they were rescued by a US aircraft carrier. Like other Vietnamese refugees from that period, she was granted permanent residency and a new life in the U.S.

We’ll hear about the origins and mission of Yulex and its long-term collaboration with Patagonia to develop natural rubber foam for wetsuits, replacing neoprene, a petroleum-based material.

Liz explains some of the key principles underpinning Yulex’s approach to innovation, and how these are fundamental to helping it scale out and create benefits right across its value network.

Liz talks us through some of the environmental and health issues associated with neoprene, and explains how Yulex is making it easier for suppliers to use natural rubber instead.

She tells us about Yulex’s latest material innovation, Yulastic filaments – a sustainable alternative to petroleum-based elastane, aka spandex.

And we hear how Yulex’s Equitable AG program supports rubber smallholders in Southeast Asia, distributing 50% of the profits back to them.

International speaker, author and strategic advisor, Catherine Weetman helps people discover why circular, regenerative and fair solutions are better for people, planet – and prosperity.

Catherine’s award-winning book: A Circular Economy Handbook: How to Build a More Resilient, Competitive and Sustainable Business includes lots of practical examples and tips on getting started.

Stay in touch for free insights and updates…

Read on for more on our guest and links to the people, organisations and other resources we mention.

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Links we mention in the episode:

Links for our guest:

LinkedIn – https://www.linkedin.com/in/liz-bui-yulex/
Yulex – https://www.yulex.com/stories

Books, people and organisations we mentioned

Join or Die documentary https://www.joinordiefilm.com/
Episode 97 Alice Mah – Plastic propaganda. Alice Mah, Professor of Sociology at the University of Warwick, helps us unpick the propaganda about plastics and their role in a circular economy https://www.rethinkglobal.info/97-alice-mah-unpicking-plastic-propaganda/

Catherine’s work:

Circular Economy Podcast on LinkedIn: linkedin.com/showcase/circular-economy-podcast/
Circular Economy Podcast website: circulareconomypodcast.com
Catherine Weetman on LinkedIn: https://www.linkedin.com/in/catherine-weetman-9419107/
A Circular Economy Handbook: How to Build a More Resilient, Competitive and Sustainable Business – buy from any good bookseller, or direct from the publisher Kogan Page, which ships worldwide (free shipping to UK and US) https://www.koganpage.com/CircEcon2
Interactive podcast index https://www.rethinkglobal.info/circular-economy-podcast-index/
Rethink Global www.rethinkglobal.info
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Guest bio

Liz Bui is Chief Executive Officer at YULEX, based in the U.S.A. (Seattle, Washington). She began her career in the biotechnology and pharmaceutical industry where she spent 20 years as Vice President, Intellectual Property Counsel and Diversity & Inclusion Officer. Liz was responsible for all areas of intellectual property, corporate and license transactional matters. Her biggest contribution was developing a formidable patent portfolio for the company’s type 1 diabetes cell therapy product, which significantly supported the acquisition of ViaCyte, Inc. for 320M USD by Vertex Pharmaceuticals, a public company (VRTX)with a 117 B USD enterprise value in 2022.

On top of managing all operational and business matters at YULEX, Liz is an intellectual property and transactional lawyer and a PhD scientist. Liz is also adjunct professor at the University of San Diego School of Law teaching patent law and mentoring law students. Originally from Vietnam, at the age of six Liz escaped Vietnam the day Saigon (now Ho Chi Minh City) fell to the North Vietnamese forces. She and her siblings, without their parents, were war refugees aboard a fishing boat until their rescue from the USS Midway. Like other Vietnamese refugees of that period, she was granted permanent residency and a new life in the U.S.

In 2022, Liz and her husband, Jeff Martin, Founder of YULEX, relocated back to the country of her birth to build YULEX’s new supply chain. In response to working with rubber smallholders in rural areas of Vietnam, Liz created the Equitable Ag program, a profit-sharing programme that benefits smallholders from YULEX sales and success. It is in Vietnam (and Thailand) that Liz and Jeff Martin innovated and developed partners for their raw materials, YULEX (natural rubber) Foam and YULASTIC (natural rubber) Filaments. Liz and Jeff are now based in the U.S. living between Seattle and San Diego, where they reside with their children.

Playlist: getting started with the circular economy…

Want to know more about the what the circular economy really is, and how it can help your business? Here’s a playlist to help you get to grips with the concept, how it creates value, and the common myths (spoiler alert – it’s much more than recycling!)

#1 What is the circular economy: A quick intro to explain what the circular economy is and why it’s important. We explore how it helps create better products and services, and at the same time helps to make a better world. I break it down into my 5 circular economy components, helping you think about each part of your business.
#2 The linear economy and your risk checklist: We dig a bit deeper into the way we do business now, the linear economy, and why that’s creating problems for business, society and our living planet. Also, we’ll look at the risks that emerge from those big-picture issues, and how they might affect your organisation.
#90 Does circular mean it’s sustainable? Catherine Weetman is worried that companies are using circular economy solutions to grow their business (and their footprints).
#101 Circular is better for people, planet and profit! How three simple strategies can help you get started with circular and regenerative solutions that are better for people, planet and profit.
#120 Priorities are changing: people find life is better when we care for and share things – circular economy strategies make that better for business, too.

And here’s Catherine’s guide: What is the circular economy?

Want to dig deeper?

Why not buy Catherine’s award-winning book, A Circular Economy Handbook: How to Build a More Resilient, Competitive and Sustainable Business. This comprehensive guide uses a bottom-up, practical approach, and includes hundreds of real examples from around the world, to help you really ‘get’ the circular economy. Even better, you’ll be inspired with ideas to make your own business more competitive, resilient and sustainable.

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Podcast music

Thanks to Belinda O’Hooley and Heidi Tidow, otherwise known as the brilliant, inventive and generous folk duo, O’Hooley & Tidow for allowing me to use the instrumentals from the live version of Summat’s Brewin’ as music for the podcast. You can find the whole track (inspired by the Copper Family song “Oh Good Ale”) on their album, also called Summat’s Brewin’. Or, follow them on Twitter.