Biodegradable Substrates for Rigid and Flexible Circuit Boards: A Review

Biodegradable materials represent a promising path toward green and sustainable electronics on a global scale in the future. Plastics play a pivotal role in contemporary electronics, including printed circuit boards (PCB), where petroleum-based polymers such as epoxies form the base insulating substrate. In this review paper, several promising bio-based alternatives to conventional PCB materials that are recently developed and investigated are stated and discussed regarding their properties, practical utilization, and further perspective. The given list includes polylactic acid (PLA), cellulose acetate (CA), polyvinyl alcohol (PVA), and others, with the development of PLA-based PCB substrates being the furthest along regarding the use in industry practice. Yet, all of the provided solutions are still only suitable for prototypes or low-cost electronics without high-reliability requirements. The reason for this is inferior mechanical and thermal properties of biopolymers compared to traditional petroleum-based polymers. Further development is therefore essential, including new types of reinforcements and other additives. However, as Life Cycle Assessment analyses discussed in the paper show, biopolymers are capable of significantly reducing the environmental impact and are likely to play a major role in shaping a sustainable path for the electronics industry, which will be a key challenge in the current decade.