Plastics have played an essential role in engineering and manufacturing. Yet they have an array of well-documented drawbacks that pose significant health hazards and ecological issues. A growing body of evidence supports the urgent need for new polymeric innovations that combine the versatility and lightweightness of conventional plastics with biodegradability and/or the use of bio-based feedstock. Namely: biopolymers or bioplastics. Manufacturers have already leveraged boron nitride as a critical additive in biopolymer manufacturing. But how, and why? This blog post will outline the importance of biopolymers, some of the underlying manufacturing challenges, and how boron nitride powders can enable their use in some applications.

What are Biopolymers?

The Institution of Chemical Engineers (IChemE) voted plastics as the sixth-most crucial chemically-engineered solution of the modern age, highlighting their versatility and lightweightness as fundamental enabling properties in a raft of application areas¹. Their persistence in nature and unavoidable fossil origin are concerning from an environmental and public health perspective. The term polymer has become synonymous with plastic, but polymers can be natural or synthetic. They are simply a class of substance composed of monomolecular chains, wherein the repeating subunit is known as the monomer. Polymers are ubiquitous–and indeed essential–in nature. Carbohydrates, lipids, nucleic acids, and proteins are all forms of polymer. Biomacromolecules like these have inspired a brand-new class of polymeric materials, known as biopolymers or bioplastics, that are renewable and often biodegradable.

 

Biopolymers are envisaged as a functional solution to various health and well-being issues. Hence, they are routinely earmarked for applications with a high risk of plastic contamination via extraction or leaching. Growing use cases for biodegradable plastics include drug transport materials, food contact materials, medical implants, tissue scaffolds, and more².The downside to this revolutionary paradigm in plastics engineering is the difficulty of replicating the chemical, electrical, mechanical, and thermal properties that make their synthetic counterparts so versatile. There are also fiscal incentives to consider. Transitioning to new production processes is a costly endeavour, so it would be ideal if new biopolymers eclipsed the performance properties of conventional plastics to add financial value as well as sustainability credentials.

Polyhydroxyalkanoates (PHAs) are one of the preferred candidate materials, as they can be produced from natural, sustainable substrates and display high degrees of engineering capacity and formability. This means that a “plastic” bottle composed of PHA biopolyester will degrade in a marine environment within 3.5 years, compared with the near invulnerability of a synthetic counterpart in the same conditions³. That said, key property measurements of biopolymers are not only reliant on the underlying substrate but various additional factors, such as the type and concentration of additives and reinforcing agents⁶. Fortunately, enormous strides have been made in this area too.

Using Boron Nitride as a Biopolymer Processing Agent

Boron nitride (BN) is a valuable ceramic material with an extremely broad range of applicability. It has proven a beneficial polymer processing aid (PPA) and has already indicated a path towards PFAS-free packaging–a critical initiative that factors into the same broad push towards safer, more bio-friendly plastic materials. In some cases, biopolymers themselves are being considered as alternatives to traditional plastics, like polyethylene, for food packaging. In addition to its beneficial lubricating properties for film processing, boron nitride is used as a nucleating agent for various polymer systems. 

Boron nitride powders have been shown to improve processing speed, dimensional stability, and–often–key physical properties of biopolymeric end-products. Boron nitride has proven to be a successful nucleating agent for P(3HB); the leading commercial grade of PHA³. As a nucleating agent, BN lowers the energy required to begin crystal nucleation and increases the crystallization rate, improving processing time. It also helps control the crystal morphology and degree of crystallinity in the biopolymer to improve its mechanical properties. The extent to which boron nitride additives can enhance fundamental properties in thermoplastics and contribute to electronic property modulation has been well-demonstrated, with critical applications for BN powders ranging from electronic cooling to improving low loss characteristics of plastic components.

Interested in Boron Nitride Solutions?

Saint-Gobain Boron Nitride is committed to helping customers reduce their environmental footprint and decarbonise critical processes. Our Boron Nitride Powder Solutions offering includes both platelet and agglomerated powders in a wide range of particle sizes, providing a suite of products to serve a variety of applications. If you would like more information about how our BN powders are applied to biopolymer processing, simply contact a member of the team today.

References

1. Interplasinsights.com. Plastics earn place in top 10 most important inventions of modern era. https://interplasinsights.com/plastics-earn-top-10-place-in-most-important-inventions-of-modern-era/
2. Baranwal J, Barse B, Fais A, Delogu GL, Kumar A. Biopolymer: A Sustainable Material for Food and Medical Applications. Polymers (Basel). 2022;14(5):983. Published 2022 Feb 28. doi:10.3390/polym14050983
3. Koller, M.; Mukherjee, A. A New Wave of Industrialization of PHA Biopolyesters. Bioengineering. 2022; 9(2): 74. https://doi.org/10.3390/bioengineering9020074