Soil Degradation of Sustainable PCB Substrates in Natural and Controlled Environments

Farkas, Csaba and Gál, László and Gyenizsei, Lívia and Harsányi, Gábor and Rigler, Dániel and Sáfár, Balázs and Gere, Dániel and Csiszár, András and Géczy, Attila (2025) Soil Degradation of Sustainable PCB Substrates in Natural and Controlled Environments. In: 2025 International Spring Seminar on Electronics Technology (ISSE).

Preview

Text FCs_ISSE2025_Paper_GA_V4.pdf Download (1MB) | Preview

Abstract

This paper compares natural and controlled soil composting, in which the degradation of flax-fiber reinforced, flame-retarded polylactic acid (PLA) composite printed circuit board (PCB) samples are monitored. We aim to investigate the structural alterations that occur over a prolonged degradation process of these biodegradable laminates, utilized as environmentally friendly substitutes for PCB substrates. The experiment involves the degradation of functional blinker circuits with surface-mounted components and blank substrate boards without a conductive copper layer. During the long-term storage, we registered the composition of the surface with Fourier-transform infrared spectroscopy (FTIR) and inspected the changes in structure with scanning electron microscopy (SEM). Compared to traditional epoxy-based (FR4) references, significant changes (at both microscopic and visible levels) and the susceptibility to natural organisms can be observed, key elements in developing a greener and more sustainable approach for future PCB designs. After 40 weeks, the FTIR analysis showed the dominant presence of PLA in the naturally degraded samples. Cellulose, which acts as component of the reinforcement, could be seen at specific locations within the cracks. The SEM study revealed contaminations and microbiological remnants on the boards' surface, along with a growing number of cracks and slight PLA deterioration. The FTIR and SEM results also highlighted the efficiency of the controlled degradation, as a significant loss of resin in the composite started after 6 weeks.

Actions (login required)

Edit Item