The water absorption behaviour of all-polypropylene composites and its effect on mechanical properties

Woven fabric based self-reinforced polypropylene (SRPP) or all-polypropylene (all-PP) composite laminates based on co-extruded tapes were analysed for water uptake and the effect that this had on mechanical properties. Comparisons were made to a commercial glass mat reinforced PP (GMT) and natural fibre mat reinforced PP (NMT). Although the all-PP composites described in this paper can show significant water uptake through the presence of voids between tapes in the crimp region, the amount of which depends on the fabric architecture and level of consolidation, and their mechanical properties are seen to be largely unaffected by water absorption, even after freezing and thawing. Conversely, the NMT used in this investigation demonstrated significant mechanical degradation with increasing water uptake.