Shape Distortion Analysis of Self-Reinforced Poly(ethylene terephthalate) Composites : The PETrifying reality!

Sammanfattning: Composite components with a V-shaped geometry have been manufactured through compression moulding of fabrics based on self-reinforced poly(ethylene terephthalate). The fabrics were subjected to a set of predetermined degrees of stretching during manufacturing with the intent to investigate its effects on shape distortions in terms of spring-in and warping. The shape distortions were also monitored as the components were subjected to sawing, a secondary heat treatment and a secondary chemical treatment. Moreover, to a limited extent the effects of weave architecture and pattern orientation were also studied as both twill and plain weaves used and the fabrics were rotated a relative angle of 45°. The shape distortions in these were then compared with shape distortions in both un-stretched self-reinforced poly(ethylene terephthalate) and traditional composite components based on glass/poly(ethylene terephthalate) and carbon/poly(ethylene terephthalate). Laser scanning measurements of the surfaces showed that fibre stretching counteracted spring-in while causing warping in the components during manufacturing. Sawing had limited effects on the components while heating increased spring-in but reduced warping. The chemical treatment increased both the spring-in and warping to a smaller and larger extent than the heat treatment, respectively. Overall the carbon fibre components performed best but the self-reinforced poly(ethylene terephthalate) performed better than the glass fibre ones. Lastly, both the secondary processing steps had a negative effect on the surface quality.