# Natural fibres for composites: wood, flax and hemp

Canonical: https://woodplasticcomposite.net/guides/natural-fibres/
Language: en
Updated: 2026-09-24
Version: 2
Review: Specialist review not yet recorded

## Summary

Natural fibre composites use fibres or particles of natural origin within a matrix. Wood and fibres such as flax, hemp, jute and kenaf are options for polymer composites. Fibre form and processing history are as important as the plant name.

## More than one kind of fibre

Natural-fibre composites include more than wood-filled profiles. Flax, hemp, jute, kenaf and other plant fibres are used in polymer composites. Automotive interior components are one established application, including liners and panels.

https://woodplasticcomposite.net/guides/natural-fibres/#section-0

## Match the fibre to the process

“Natural fibre” is too broad a description for a purchasing specification. Ask whether the material is flour, chopped fibre or a mat, and request information about particle size, moisture and batch consistency. The useful comparison is the fibre as supplied to your process.

https://woodplasticcomposite.net/guides/natural-fibres/#section-1

## What to ask a supplier

Request the source, processing method and quality limits alongside a physical sample. Agree how incoming material will be checked. A locally available residue may be attractive, but a repeatable supply specification is more useful than an appealing origin story.

https://woodplasticcomposite.net/guides/natural-fibres/#section-2

## Look at the complete component

Compare finished parts under the intended conditions. Do not transfer results for one fibre, matrix or manufacturing method to another without evidence. Keep sourcing claims separate from claims about strength, durability or environmental impact.

https://woodplasticcomposite.net/guides/natural-fibres/#section-3

## Key points

Particle-size distribution
Length distribution after processing
Forming process and resin system

## Comparison

Topic | Evidence or meaning | What to check
Wood flour | Particulate feedstock | Particle-size distribution
Chopped fibres | Discrete fibre lengths | Length distribution after processing
Fibre mats | Sheet-like preforms | Forming process and resin system

## Does natural fibre mean biodegradable composite?

No. An ingredient of natural origin does not establish biodegradability of the whole fibre–polymer product.

## Can one plant fibre replace another directly?

Do not assume direct substitution. Validate the supplied fibre, processing behaviour and finished component.

## Sources

1. USDA Forest Products Laboratory · Natural fibers — https://research.fs.usda.gov/treesearch/40826