Effect of dyeing on melting behavior of poly(lactic acid) fabric

The effect of the dyeing on the melting behavior of poly(lactic acid) fabrics was investigated by differential scanning calorimeter. The DSC melting peaks at 10°C min-1 of the untreated poly(lactic acid) fabric were observed at a temperature higher than those of the dyed fabrics. The restricting force from the extended tie molecules along the fiber axis seems to decrease in the dyeing process. When the sample was rapidly heated, the crystallites melted at lower temperatures since recrystallization was restricted. It was estimated, based on the heating-rate dependency of melting behavior, that the original crystallites of the untreated sample melted at 146.1°C and those of the dyed samples melted at higher temperatures, suggesting that their crystallites are grown to be more perfect in the dyeing process.