Differential scanning calorimetry and elasticity of textured, heat set and mechanical strained polylactide multifilaments

Industrially textured PLA multifilaments were heat set under different conditions at 110 ºC for 1 min and subjected to one cycle of deformation up to 20%. Thermal transitions of the original textured, heat set and cyclic strained filaments were measured using differential scanning calorimetry from 25 to 250 ºC. Cyclic deformation induces an endo-exo transition at peak temperatures between 55 - 60 ºC that is not observed in the original textured and heat set multifilaments. There is another endo-exo transition with peak temperatures between 67 and 72 ºC in all filaments, the intensity of which varies according to texturing conditions, heat setting and cycle strain. Texturing conditions, heat setting and cyclic strain play a role in thermal transitions, the strain at breaking and elastic properties of the filaments. The crystallinity and magnitude of the endo-exo thermal events detected by DSC are related to the strain at breaking and elasticity of polylactide textured multifilament