Thermomechanical characterisation of soft potting materials and stress reduction by compressibility

For the rapidly increasing use of electronic controllers and sensors under harsh environmental conditions, the corresponding electronic assemblies must be protected from external influences by polymer encapsulation. However, this polymer encapsulation leads to mechanical stress on the component under temperature load, which can lead to deformation and subsequent breakage or shearing of electronic components. This paper focussed on the development and research of stress-reducing organic potting compounds that can intrinsically prevent hydrostatic stresses. Therefore, a polybutadiene compound was filled with stress-compensating additives and was subsequently characterised. The effect of the stress-reducing properties of the material was demonstrated in compression tests and under cycling thermal loading using a moulded and assembled printed circuit board.