Bioplastics in engineering applications: opportunities and challenges

Plastics are indispensable in modern life. In almost every industry, from the automotive industry to medical technology and packaging technology, they perform essential tasks. However, conventional plastics are increasingly criticised: they are based on finite fossil raw materials, cause high CO₂ emissions during production and contribute massively to the global waste problem. Against this background, bioplastics are gaining importance as a potentially sustainable alternative.

Particularly exciting is the use of bioplastics in technical applications. Here, significantly higher demands are placed on load-bearing capacity, long-term behaviour and processability than in simple consumer products. This article examines the question of whether bioplastics are up to these demands, what development potential exists and where limits currently still lie. Both technical and economic aspects are considered in order to paint a realistic picture of the status quo and the future prospects.

What are bioplastics?

The term "bioplastic" is not clearly defined and can refer both to the origin of the raw materials and to biodegradability. To avoid misunderstandings, it is important to distinguish between different categories:

1. Bio-based, non-biodegradable plastics: These plastics consist of renewable raw materials such as sugar cane or maize, but have a chemical structure that corresponds to that of fossil-based plastics. Examples are bio-PE (polyethylene) and bio-PET (polyethylene terephthalate). They are materially identical to their fossil counterparts and can therefore be used in existing applications without any problems.
2. Bio-based, biodegradable plastics: This group includes materials such as PLA (polylactide) or PBS (polybutylene succinate), which both consist of renewable raw materials and can be biodegraded under certain conditions. They offer potential for applications with a limited service life, but are often mechanically less resilient.
3. Fossil-based, biodegradable plastics: These plastics are made from fossil raw materials, but are designed in such a way that they are biodegradable under industrial composting conditions. One example is PBAT (polybutylene adipate terephthalate). This variant offers interesting possible applications in the packaging sector, but is only conditionally sustainable.

The variety of bioplastics shows that they are not a uniform material, but a broad class of materials with different properties and fields of application. For technical use, above all those bioplastics are suitable that are mechanically resilient, thermally stable and chemically resistant. In this context, bio-based high-performance plastics and fibre-reinforced biopolymer compounds are gaining increasing importance.

Technical requirements for plastics

Engineering plastics are used in demanding areas such as mechanical engineering, the automotive industry or medical technology. The typical requirements are:

• High-temperature resistance
• Mechanical load-bearing capacity
• Chemical resistance
• Dimensional accuracy and dimensional stability
• Good machinability or processability

Many bioplastics can so far only meet these requirements to a limited extent, but there are promising developments.

Opportunities of bioplastics in technical applications

Resource conservation and CO₂ reduction

Bio-based plastics use renewable raw materials such as maize starch, sugar cane or cellulose. This can reduce dependence on fossil resources.

Innovative material design

Through copolymerisation, additivation and fibre reinforcement, bioplastics can be specifically adapted to technical requirements. Materials with improved heat resistance, impact toughness or chemical resistance are created.

New fields of application

Bioplastics are increasingly used in the following areas:

• Electronics housings
• Lightweight components in automotive engineering
• Medical consumables
• Packaging for technical products

Legal and social impulses

The increasing regulation of single-use plastics and the rising demand for sustainable products promote innovations in the field of engineering bioplastics.

Challenges in the use of bioplastics

Limited material properties

Many bioplastics (e.g. PLA) exhibit lower temperature resistance or brittleness. High-performance biopolymers such as bio-PA or bio-based PBT are under development, but expensive.

Costs and availability

The production of bio-based plastics is often more expensive than that of conventional materials. Raw material availability and scaling also pose a challenge.

Processability

Not all bioplastics can be processed without problems with existing machines and processes (e.g. injection moulding, extrusion). Modifications to tools or processes are often necessary.

Standards and approvals

Technical applications require specific standards (e.g. for flame protection, long-term behaviour, food contact) that many bioplastics do not yet meet.

Outlook and development trends

Research in the field of engineering bioplastics is dynamic. Developments focus on:

• Fibre-reinforced biopolymers
• Bio-based high-performance plastics (e.g. bio-PA11, bio-PBT)
• Hybrid materials made from bio-based and engineering polymers
• Recycling and circular economy concepts

In the long term, bioplastics could play a key role in sustainable product development and the circular economy of technical industries.

FAQ – Frequently asked questions about bioplastics in technical applications

Are bioplastics really biodegradable? Not all bioplastics are biodegradable. The decisive factor is the chemical structure, not the origin of the raw material.

Which bioplastics are suitable for technical applications? Examples are bio-PA, bio-PET, PHA or fibre-reinforced PLA compounds. Their suitability depends on the specific field of application.

How do bioplastics compare with POM, PA or PC? Still inferior in terms of temperature and chemical resistance, but with increasing progress in material modification and fillers.

Is the use of bioplastics economically worthwhile? Depending on the application and quantity, it can pay off, especially if sustainability is a selling point or regulatory requirements exist.