Melt spinning of propylene carbonate-plasticized poly(acrylonitrile)-co-poly(methyl acrylate)

The primary use of poly(acrylonitrile) (PAN) fibers, commonly referred to as acrylic fibers, is in textile applications like clothing, furniture, carpets, and awnings. All commercially available PAN fibers are processed by solution spinning; however, alternative, more cost-effective processes like melt spinning are still highly desired. Here, the melt spinning of PAN-co-poly(methyl acrylate) (PMA) plasticized with propylene carbonate (PC) at 175 degrees C is reported. The use of methyl acrylate (MA) as comonomer and PC as an external plasticizer renders the approach a combination of internal and external plasticization. Various mixtures of PAN and PC used in this work were examined by rheology, subjected to melt spinning, followed by discontinuous and continuous washing, respectively. The best fibers were derived from a PAN-co-PMA copolymer containing 8.1 mol-% of MA having a number-average molecular weight M- n of 34 000 g/mol, spun in the presence of 22.5 wt.-% of PC. The resulting fibers were analyzed by scanning electron microscopy and wide-angle X-ray scattering (WAXS), and were subjected to mechanical testing.