Study of the influence of stretching on the macromolecular dynamics of polylactide by means of Xray Photon Correlation Spectroscopy (XPCS)

It is know well known that the structural evolution of a thermoplastic polymer upon stretching is closely linked with the stretching conditions (i.e. stretching temperature and speed). Former studies carried out by our group have shown that the nature of the strain-induced phase (i.e. cristalline, mesomorphic...) is also related to the macromolecular dynamics into the material and that relationships exist between these characteristic relaxation times, the nature of the strain-induced phase and the stretching conditions. However, up to now the determination of the macromolecular dynamics, in situ upon stretching, remains a challenge. The goal of this work is thus to measure the influence of orientation on the macromolecular dynamics of a polymer upon stretching, in situ, using the XPCS technique (which is one of the few allowing such measurements) in order to definitely confirm the relationships existing between the macromolecular dynamics and the nature of the strain induced-phase