Melt‐spun poly(lactic acid) fibers modified with soy fillers: Toward environment‐friendly disposable nonwovens

ABSTRACT Poly(lactic acid) (PLA) has a significant potential as a biodegradable polymer, but its high cost and slow biodegradability restrict its use in disposable products. This study establishes a novel route to accomplish both objectives by the addition of low‐cost soy fillers into PLA, which reduced material cost and increased the degradation rate of resulting soy‐PLA fibers. Due to partial thermal degradation of soy fillers at PLA melt temperature, they could be melt‐compounded into PLA up to 5 wt%. Fine continuous fibers (D ∼ 25‐50 μm) were successfully produced via melt spinning, and further melt‐consolidated into prototypical nonwovens. The tensile strength of soy‐PLA fibers containing soy reside and soy flour were 56 ± 9 and 44 ± 5 MPa, respectively. Although slightly lower than that of neat PLA fibers (74 ± 2 MPa), the fibers possessed adequate tenacity for use as nonwoven fabrics. Fiber modulus remained unaffected at about 2.5 GPa. The soy‐PLA fibers displayed a relatively rough exterior surface and provided a natural‐fiber feel. The overall degradation of soy‐PLA fibers was accelerated about 2‐fold in a basic medium due to the preferential dissolution of soy that led to increased surface area within the PLA matrix indicating their potential for use in biodegradable nonwovens.