A sustainable and hydrolysis-free
dyeing process was developed
for polylactic acid (PLA) fibers. PLA is a biobased alternative to
petroleum based polyethylene terephthalate (PET), which is the most
widely used textile fiber. However, the hydrolytic degradation of
PLA fibers under the conventional aqueous dyeing conditions limited
its applications in textile industry. A new solvent dyeing process
was developed using liquid paraffin as a nonaqueous dyeing medium.
High quality dyed PLA fabrics were obtained without consuming water
and auxiliaries. Minimal strength loss of dyed fibers was achieved
by postheat setting treatment. The 3R principle (reduce, reuse, and
recycle) was implemented to ensure the environmental friendliness
of solvent dyeing process. The result of a 9-cycle reuse sequence
demonstrated excellent color consistency of dyed PLA fabrics. The
sustainability of our new dyeing process was quantified in the framework
of environmental-health-social impact. The dyeing process sustainability
index indicated that the solvent dyeing process was preferred over
the aqueous dyeing. The method developed in the present work enabled
the practical applications of PLA as textile fibers. It represented
an important step toward a sustainable textile industry