problems with natural fibers

Problems & Solutions – Compounding Natural Fibers Into Plastics

Plastic compounders have been trying to figure out how to integrate sustainable materials into their products for years. The problem is, that sustainable materials feel like some made-up fairytale to a plastics industry professional who has been around for decades.

Everyone knows that bioplastics have hefty price premiums, performance issues, and production timelines that are many years away. So, the obvious solution has always been bio-based additives. 

The problem is that bio-based additives do not naturally bond and perform inside the plastic. This is a chemistry and physics problem that Heartland set out to solve years ago. 

Problems with Natural Fibers

Bulk Density

When the engineers at Heartland first worked with plastic compounders, they told us that our materials were too fluffy. This caused feeding problems and prevented us from loading hemp fibers above a 10% load rate.

Of course, to replace mineral-filled plastics that used 20% – 50%+ additives, we had to figure out how to increase the percentage of hemp that could be loaded into the plastic. 


Handling hemp powders had most plastic compounders dealing with bio-based dust and powder for the first time. Every compounder has handled minerals, but few have handled natural fibers. 

This presented new frustrations for plastic compounders that see an opportunity to win with natural fiber additives.


Natural fibers can catch fire if they’re mishandled. Optimizing the fiber so that it reduces ignition and flammability concerns is important for plastic compounders. This initiative is at the Heart of Heartland’s material, product, and formulation development.


Natural fibers will absorb ambient moisture. This can create handling problems in different regions and weather conditions across the world. 

If a plastic compounder leaves a bag of natural fibers on the dock or opens it for too long, the fibers will require further drying.


Natural fibers and petroleum products have radically different chemistries that prevent them from bonding together without proper engineering. A lack of bonding creates a lack of performance.

This was one of the greatest challenges our engineering team faced, and ultimately solved.


Plastic compounders also noticed agglomeration when compounding hemp fibers in their twin screw extruders. This prevented us from getting a consistent product where the hemp fibers were evenly dispersed in the plastic.

The R&D leaders we were working with also had concerns about creating a reliable supply chain with product consistency. How can a Fortune 500 transition its raw material supply chain over if it can’t access a reliable and consistent supply of products? The fact is, they can’t. 

We were encouraged to create consistency around the size, moisture content, and aspect ratio of the materials we were distributing. 

Much like bonding, the problems with agglomeration and dispersion also created performance issues when filling plastic with hemp.

Turning Problems Into Opportunities

After our first round of testing, it felt like we had been to war. All the data was telling us we were fighting an uphill battle. 

As plastic compounders were telling us all the problems they were having with our natural fibers, the feedback hurt. But, on the other side of that coin, we were uniquely positioned to solve the problems of compounding natural fibers into plastics. 

We completely reengineered our equipment stack to solve the problems of the plastic compounders. We worked alongside leaders across the plastic industry to create a high-performance carbon-negative additive that could be used as a drop-in replacement for talc, fiberglass, and calcium carbonate. 

Through years of research and development, we created our Imperium Masterbatch

Engineered For Mass Manufacturing

Imperium Masterbatch is for brands, and suppliers that are looking for high-performance carbon-negative plastic additives to help them predictably reduce the cost, weight, and carbon footprint of their products.

Our products are designed to bond and perform inside any thermoplastic without any retooling costs. 

Heartland supplies lower-carbon-footprint materials to help manufacturers create stronger, lighter, cheaper, and more sustainable plastic products.

If you are a brand or supplier, reach out to our engineering team now to find out how to embed carbon-negative additives into your plastics.

Join us as we make a world out of hemp.

Heartland Team

Problems with Natural Fibers Infographic