Fig. 6From: Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealingRaman spectra of PLA (a, b) and PLA-WS2 0.6% (c, d) measured on UNST, ST0, ST3 and ST10 samples. The spectra have been normalized with respect to the intensity of the PLA band at 1095 cm− 1Back to article page