Polymer Engineer

Natural Negative is a materials science company optimising biomaterials science with AI. We design compostable formulations that match or surpass conventional plastics: production-ready and drop-in compatible with existing manufacturing lines.

We believe everything humans encounter and consume should make them healthier. The biomaterials that could deliver that already exist; the industry hasn't yet made them practical to adopt at scale. We're optimising that: faster, cheaper, less risky.

We're investor-backed, with active Innovate UK grants and partnerships across leading research and innovation organisations. Our lab is at Plus X Innovation Hub, Brighton.

The role

We're looking for a Polymer Engineer to contribute to our materials lab as we grow. You'll be hands-on with extrusion and polymer or plastics processing, prepare and dispatch samples for customer and grant projects, and help build the systems and standards that let the lab scale.

You'll work closely with our Lead Polymer Scientist, who sets scientific direction. Your job is to translate that direction into disciplined, well-documented lab work, and to bring your own polymer or plastics processing judgement to how we run.

What you'll do

• Run polymer processing. Work hands-on with extrusion and other processing operations. Develop improvements that make the work faster, more consistent, and more repeatable.
• Support lab operations. Sample preparation, equipment operation, workspace organisation, safety, and keeping things R&D-ready.
• Test and validate. Carry out characterisation and testing of new formulations, and where a method doesn't exist yet, work out a practical way to get the data.
• Make things. Manufacture prototypes and production samples. Use CAD and workshop skills to design and build fixtures, tooling, and test rigs where useful.
• Deliver for customers. Prepare and dispatch samples, coordinate with external testing facilities and manufacturing partners, keep multiple workstreams moving on time.
• Contribute to funded R&D. Participate directly in our Innovate UK-funded projects.
• Build the standards. Develop and maintain SOPs, risk assessments, COSHH documentation, and lab notebooks to the standard our funders, partners, and customers rely on.

In your first six months

You'll be up to speed on our current polymer formulations, contributing to process improvements, and helping build the systems that let the lab scale as we grow.

How we work

• Truth and open communication. We say what we think, kindly. We're open about our mistakes.
• Wellbeing and nurture. We look after each other and ourselves. Life outside work matters.
• Integrity and discipline. We do what we say we'll do. We take our craft seriously.
• Warmth. We treat each other well.
• Curiosity. We're here because the problem is interesting. We learn out loud.
• Joy. We enjoy the work, even when it's hard.
  

Sprint culture doesn't solve materials science problems. We move thoughtfully.

Requirements

Must-have

• Hands-on experience with polymer or plastics processing, ideally including extrusion. Usually 2+ years of industry work, or equivalent experience.
• A process improver. You don't just execute processes, you improve them. You can point to a specific time you took a process and made it faster, more consistent, or more repeatable.
• Self-directed. You set your own pace and priorities.
• Comfortable working alongside a materials scientist and translating scientific direction into lab plans.
• Rigorous with data, documentation, and traceability.
• Collaborative. You operate well in a small, flat team and give and receive feedback well.
  

We care more about what you've done than how long you've been doing it.

Nice to have

• COSHH, lab H&S practice, writing SOPs or risk assessments
• Coordinating with external manufacturing or testing partners
• Prior experience in a startup or small-team environment
• Direct experience with bioplastics, compostable materials, or biopolymers
• CAD (SolidWorks, Onshape, or Fusion 360) and basic machining
• Grant reporting experience, particularly Innovate UK

Practical details

• Location: based at our lab at Plus X Innovation Hub, Brighton
• Contract: full-time, permanent
• Right to work: you must be UK-based with the right to work in the UK. We are unable to consider applications from candidates residing outside the UK or requiring visa sponsorship.
• Applications: rolling basis. We will close applications once we have received enough strong candidates, so apply early.

Benefits

• A competitive salary + meaningful equity.
• A direct working relationship with the founders. No layers between you and the people making decisions.
• 28 days including public holidays.
• Workplace pension scheme.
• A team that doesn't reward presenteeism and doesn't micromanage. Family, rest, and time to think are how good work gets done, not what gets traded to do it.