The effect of artificial weathering on PP coextruded tape and laminate

The aim of this work was to analyse the influence of artificial weathering on polypropylene (PP) self-reinforced composite both as fabric constituent (tape) and as laminate. Particular attention has been focused on the interaction between radiation and material microstructural characteristics, especially for the selective action that the former causes in PP amorphous regions. The evaluation of carbonyl index performed by Fourier Transform Infrared (FT-IR) spectroscopy has highlighted that tapes are more prone to degradation since their drawn structure induces internal stress. Differential scanning calorimetry (DSC) measurements have denoted a shift towards lower temperature of PP melting peak. While crystallinity determination performed by DSC and FT-IR spectroscopy has underlined an increasing trend for laminate over exposure time due to the higher amount of amorphous phase, Raman spectroscopy has revealed that photo-degradation induces a rise of the isomeric defect fraction, limiting chemi-crystallisation both for tapes and laminates.