Designing polylactide/clay nanocomposites for textile applications: Effect of processing conditions, spinning, and characterization

An experimental study was carried out to design polylactide (PLA)-clay nanocomposites for developing fibers. PLA and 1-1.0 wt % of a selected organomodified bentonite (Bentone (R) 104-B104) were melt mixed to examine the effect of processing conditions (temperature, shear, residence time) on the morphology of performed polymer nanocomposites (PNC). Because of a good compatibility with PLA matrix, the dispersion of B104 occurred under different conditions without difficulty, and a similar morphology was obtained. The results obtained showed that at low temperature of mixing, the shear stress exerted on polymer has a key role on the extent of intercalation and delamination. Upscale experiments were further performed using optimized conditions and 4 wt % B104 was added to PLA matrix by melt blending to produce PNC for spinning. Then, the recovered PNC were melt spun to produce multifilaments yarns, and it was demonstrated that surprisingly, it is not necessary to use a plasticizer to spin a blend with 4 wt % B104. The properties of the yarns have been studied in terms of clay dispersion as well as thermal, mechanical, and shrinkage properties. B104 could be added up to 4 wt % into PLA without detrimentally sacrificing the tensile strength of melt-spun filaments, especially at high draw ratio. Interestingly, the PNC-based multifilaments were knitted and the flammability studied using cone calorimeter at 35 kW/m(2). A strong decrease, up to 46%, of the heat release rate was measured. (C) 2008 Wiley Periodicals, Inc.