Achieving sustainability is an important challenge that requires new approaches to the design and production of materials and products. Bio-based plastics offer a promising opportunity in the search for sustainable materials. Derived from renewable feedstocks such as plants and agricultural waste, they offer an alternative to traditional fossil-based plastics. Yet, despite their potential, bio-based plastics are mainly used in packaging and other short-lived products, and the opportunities of using bio-based plastics in durable products remain largely underexplored.

This dissertation explores how bio-based plastics can be incorporated into the development of durable products for a circular economy. It examines the opportunities, challenges, and decision points faced by product developers when working with bio-based plastics, moving beyond simple material substitution to rethinking product design and development. The dissertation provides practical guidance to support product developers in making informed, sustainable choices when developing durable, circular products with bio-based plastics.

Replacing fossil-based feedstock with renewable alternatives is a crucial step towards a circular economy. The bio-based plastics currently on the market are predominantly used in single-use applications, with remarkably limited uptake in durable products. This study explores the current state of the art of bio-based plastic use in durable consumer products and the opportunities and barriers encountered by product developers in adopting these materials. A design analysis of 60 durable products containing bio-based plastics, and 12 company interviews, identified the pursuit of sustainability goals and targets as the primary driver for adopting bio-based plastics, despite uncertainties regarding their reduced environmental impact. The lack of knowledge of bio-based plastics and their properties contributes to the slow adoption of these materials. Furthermore, the lack of recycling infrastructure, the limited availability of the plastics, and higher costs compared to fossil-based alternatives, are significant barriers to adoption. Product developers face significant challenges in designing with bio-based plastics, but opportunities exist; for example, for the use of dedicated bio-based plastics with unique properties. When designing with bio-based plastics, product developers must think beyond the physical product and consider sourcing and recovery, which are not typically part of the conventional product design process.

Bio-based plastics are gaining attention as a sustainable, circular alternative to the current, petrochemical-based plastics. The main application of bio-based plastics is in single-use packaging with short lifetimes. Extending the application of bio-based plastics products towards durable consumer products requires the involvement of different value chain actors. An online interactive workshop, with 46 participants representing the entire value chain, produced a list of drivers for using bio-based plastics in durable consumer goods and barriers to overcome. The primary barriers to using bio-based plastics in durable products were related to their underdeveloped value chain and a need for more knowledge. The underdeveloped value chain was associated with high costs and no infrastructure for recovery at end-of-life, reducing potential environmental benefits. Participants indicated that they did not expect the value chain to mature without substantial government stimulations. Participants also noted a lack of knowledge among value chain actors as well as end-users. Value chain actors expressed that they need more clarity about what bio-based plastics are available and how they can be used in a sustainable way. While the market demand for sustainable alternatives is growing and bio-based plastics are a valuable marketing tool, users are poorly informed, and marketing should be thoughtful to avoid greenwashing.

This design review evaluates the use of bio-based plastics in durable consumer products. The main question is: how does the use of bio-based plastics influence the product’s design, functionality, marketing & communication, and sustainability? Although higher material prices would lead one to expect that higher value applications would be targeted, research shows bio-based plastics are mainly used in short-lived applications like packaging. This study investigates their use in durable consumer products through a design review. The results indicate that bio-based plastic usage is still in its early days in durable products. Bio-based plastics appear to be utilized as straightforward replacement of fossil-based plastic. Designers are not yet using the unique properties of bio-based plastics in the design of their products. Companies mainly exploit the green image of bio-based plastics in their marketing & communication. Their focus is on the renewable feedstock and not on sourcing, or on recovery at end-of-life.