Harald Martini

Influence of electron beam irradiation on electrical properties of engineering thermoplastics

Engineering thermoplastics are widely used as insulation material for low voltage products. The requirements becoming more and more demanding. For high temperature applications the performance of standard Polyamide (PA) and Polybutylene terephthalate (PBT) is insufficient. It is well known that crosslinking by electron beam irradiation improves the temperature resistance and tribological properties of these thermoplastics. This paper studies the influence of irradiation cross-linking on the electrical properties of several engineering thermoplastics. An increase in alternating current (AC) breakdown strength for cross-linked PA6.6 and PA12 could be observed. Electron beam irradiation did not improve the resistance to tracking of PA6.6. Crosslinking did reduce the dielectric constant of PA6.6, PA12 and PBT.

Electro-thermal aging behaviour of thermoplastic compounds

Improved recyclability and cost pressure encourage the use of thermoplastics as electrical insulation material for demanding electrical applications. Besides their basic mechanical, thermal and electrical properties it is of interest to study the aging behavior of these thermoplastic materials. In this paper a non-standard test method is presented, where rod-rod shaped test samples have been exposed to electro-thermal stress. The samples have been aged at elevated temperature under alternating current (AC) field until breakdown occurred. Several thermoplastic materials were tested and differences in performance due to fillers and additives were investigated.