Zusammenfassung
Ultra-small-angle X-ray scattering (USAXS) and small-angle X-ray scattering (SAXS) measurements are presented for poly[(R)-3-hydroxybutyrate] (PHB) crystallized at room temperature. The USAXS patterns indicated that the spherulites had a radially orientated fibrillar nanostructure with fractal geometry over a length scale ranging from 12 nm up to at least 300 nm, with a mass fractal dimension of ...
Zusammenfassung
Ultra-small-angle X-ray scattering (USAXS) and small-angle X-ray scattering (SAXS) measurements are presented for poly[(R)-3-hydroxybutyrate] (PHB) crystallized at room temperature. The USAXS patterns indicated that the spherulites had a radially orientated fibrillar nanostructure with fractal geometry over a length scale ranging from 12 nm up to at least 300 nm, with a mass fractal dimension of approximately 2.7 in aged samples. The SAXS patterns indicated that the fibrils themselves were built up of bundles of crystalline lamellae separated by layers of disordered material, with a period length of approximately 6 nm. The SAXS measurements during primary crystallization gave an initial fractal dimension of 4 during spherulite growth, due to the sharp phase boundary between the spherulites and the melt. (C) 2004 Society of Chemical Industry.