Nucleation of Poly(lactide) on the Surface of DifferentFibers

The nucleation process of poly(lactide) (PLA) on a series of fibers was studied by means of in situ polarized optical microscope during crystallization. Several synthetic and natural fibers (polyethylene terephthalate, carbon, Kevlar, glass, hemp, linen, and cellulose) were employed and compared to custom-spun fiber of stereocomplex (SC) enantiomeric PLA blend. Meaningful differences in the nucleating ability toward PLA could be found for all of the considered fibers. SC PLA fibers display extremely high nucleating efficiency, with the development of a continuous transcrystalline morphology on their surface, up to high crystallization temperatures. Quantitative measurement of the nucleation rate allowed a comparison of the different fiber substrates in the light of classical heterogeneous nucleation theory, by considering the interfacial free-energy difference parameter, Δσ, directly related to the nucleation barrier. The topography of the fibers surface was investigated by atomic force microscopy and ten...