Bio-Composites: can plant-based additives and fillers become mainstream? Kathrin Schilling, BioPowder’s founder & director reports.
BioPowder is specialist supplier of micronised fruit stone powders as bio-based ingredients, additives and abrasives. Derived from food processing side streams, the company’s products support a circular economy and enable manufacturers to reduce their environmental impact.
Founded in 2017 and headquartered in Malta, the company sources from the Mediterranean region and manages production in Southern Spain. BioPowder is part of a sustainable supply chain that focuses on upcycling agricultural by-products (not crops), taking a local approach that reduces waste and does not disrupt the food chain.
Bio-composites — composite materials made from natural fibres and/or bio-based resins — are increasingly prevalent and have the potential to become the material of choice in the future. Their popularity is largely due to rising environmental concerns but can also be attributed to their versatility and excellent mechanical properties.
According to Future Market Insights, the global bio-composites market is expected to increase at a robust CAGR of 16%, from US$25 billion in 2021 to US$128bn in 2032. A key factor driving this growth is the materials’ environmental sustainability. Made from renewable resources such as natural fibres, bio-composites create less of an impact on the environment than traditional composites that are derived from fossil or non-recyclable raw materials.
A raw material that has been gaining wider attention of late is the olive pit, a by-product from the olive oil mill. Olive oil manufacturing involves compressing of the olive (as a whole), which produces a solid residue of pulp, peel, and fragmented pits. In the past, raw olive pits have mainly been used for combustion.
According to the International Olive Council , an estimate of 3.1 million metric tonnes of olive oil was produced during the season of 2021/22, up 2.9% from the year before. This translates to a massive amount of olive pomace left behind, which comes with certain disposal challenges because of its fat and salt content. Fortunately, innovation and new technology have emerged to recover this waste stream: olive pits can be upcycled into high-performance functional powders – fully circular additives with desirable properties for modern composite formulations.
Specialised machines are used to process fresh olive cake in a moist state, and olive pit fragments are separated from pulp and shell through a centrifugation process. The fragments are then mechanically cleaned, dried, screened and micronised into well-defined particle fractions. Through this complex treatment process, BioPowder recovers light beige powders that are neutral in smell and taste. These natural additives, which BioPowder markets as Olea FP (Functional Powders), can be further functionalised, which makes them valued components for a variety of applications.
Proven applications of refined olive stones in composites
The base material of Olea FP – refined olive stones – essentially consists of cellulose, hemicellulose, and lignin. It is an organic material that stands out from among other biomasses due to its unique properties. As a result, micronised olive stone powders are powerful functional fillers, reinforcing fibres and texture particles for composites. Incorporating them in material formulations comes with a myriad of possibilities.
In thermoplastic composites (e.g. PP, PE, PLA, PHA, etc.), functional olive stone powders are best incorporated in the pre-mixing or pre-heating stage of the compounding process. Smooth dispersion and particle stability ensure reliable functionality in both conventional and biodegradable compounds, and similar results can be obtained in 3D printing filaments.
In thermostable resin composites, Olea FP can add reinforcing properties besides unique texture effects. Bespoke grain sizes and coloured particles open new doors for bio-innovation, such as in the field of methyl methacrylate (MMA) composites or epoxy coatings.
Rubber is a major source of microplastics, mainly caused by the abrasion of vehicle tires or shoe soles. Filling synthetic rubber compounds with natural olive stone powders can help reduce the environmental impact while enhancing lifespan and mechanical properties.
And in cementitious composites, such as reinforced concrete, olive stone powder can boost adhesion and surface finish of the material while adding strength and durability. The same goes for ceramic composites where the particles are also efficient porosity enhancers.
Moving in the right direction
While there is still work to be done to ensure that bio-composites become the norm rather than the exception, there are signs that suggest that the industry is moving in the right direction. Lifecycle assessment has become an industry standard, and the carbon footprint of raw materials a central criterion for purchasing decisions. Amidst the diversity of bio-composite formulations, manufacturers, and end users increasingly value compostability over industrial degradability and plant-based over fossil. With this in mind, BioPowder looks forward to partnering with companies to create a better world for future generations.