High-performance glass-fibre reinforced biobased aromatic polyamide in automotive biofuel supply systems

Abstract

The increase in service temperature and the use of renewable but also more aggressive biofuels such as biodiesel have remarkably raised demands for the durability of polymer components used in automotive fuel systems. The commonly used aliphatic polyamides (PAs) can here be problematic to use in (bio)diesel systems at high temperature in locations such as fuel pipes and fuel filter housings. In the present work, the ageing behaviour of a new class of easily melt-processable glass fibre-reinforced highly-biobased semi-aromatic polyamides (polyphthalamide, PPA) was investigated in very demanding environments (petroleum diesel (B0) and its commercial blend with 20 vol% biodiesel (B20)) at high temperature. The results showed that the PPA matrix had better barrier properties towards both petroleum and bio-based diesel compared to conventional PA12, as revealed by its lower and slower fuel uptake. The sorbed fuels plasticized the composite, decreasing the glass transition temperature (Tg), with B20 having a larger plasticizing effect on PPA than B0. Notably, the mechanical properties of the PPA composite were not negatively affected even after long exposure to both B0 and B20. This was due to the low level of fuel uptake, high Tg and intact interface between the glass fibres and PPA matrix.