Effects of cross head speed on properties and energy absorption of sandwich AL/PU-PTFE foam composite

Abstract

This study to investigates the relations between cross head speed and the energy absorption of sandwich Al/PU/PTFE foam composite. The PU foam was prepared using the palm oil based polyol and isocyanate (MDI) with ratio of 1:1.1. The purpose addition of 2% PTFE filler for improve the properties of the foam such as resistance when load applied on composite structure according to stiffness, strength, thermal stability and other structural properties. The flexural properties and energy absorption was study by using different cross head speed (5, 10, 15 and 20 mm/min) on PU/PTFE foam composite and sandwich foam composite. Moreover, the effect of PTFE on X-Ray diffraction, DSC, TGA and FTIR in PU foam composite were also investigated. It was found that PU/PTFE showed the lower crystallinity index as compared to PU foam due to the poor arrangement of PTFE. The DSC results indicate that adding of PTFE gives the higher heat stability even heated above its crystalline melting temperature of 327 °C while PTFE also shows better thermal resistance than PU foam for TGA result. That means, PU/PTFE foam composite takes longer time to fully degrade than PU foam. Furthermore, the medium crosshead speed (10 and 15 mm/min) shows the higher flexural strength and flexural modulus for PU foam and PU/PTFE either in composite or sandwich foam. Meanwhile, the energy absorption of PU and PU/PTFE was increases due the lower cross head speed and this can delay the crack failure. In sandwich foam, the ductility of Al sheet used to increase the energy absorption and improved the strength of sandwich foam.