Abstract

BRITO, Yelitza et al. Estudio de la miscibilidad, morfología y cristalización de las mezclas POLI(P-DIOXANONA)-POLI(E-CAPROLACTONA) (PPDX/PCL). Rev. LatinAm. Met. Mat. [online]. 2006, vol.26, n.1-2, pp.61-75. ISSN 0255-6952.

This work reports the preparation of a novel biodegradable polymer blend composed by Poly(p-dioxanone) and Poli(e-caprolactone) in a wide composition range. Firstly, blends of high molecular weight materials commercially available were prepared and these turned out to be immiscible. The immiscibility was demonstrated by the lack of variation of the relevant thermal transitions determined by Differential Scanning Calorimetry (DSC) and by the two phase morphology that was observed by Scanning Electron Microscopy (SEM) and by Polarized Light Optical Microscopy (PLOM). Additionally, the spherulitic superstructure of each phase remained unaltered besides the presence of the second phase and no modification of the spherulitic growth rate of the PPDX phase was found. Attempts to try to compatibilize these high molecular weight blends by several strategies were unsuccessful. The miscibility study was also extended to low molecular weight PPDX and PCL without and with the addition of a PPDX-b-PCL diblock copolymer of comparable molecular weight. Even under these more favourable conditions the blends were still immiscible, a fact that is surprising in view of their similar chemical structure. Even though the blends are themodinamically immiscible, physical interactions between the components were detected like apparent impurities transfer and a nucleating effect of the PPDX on the PCL in a certain composition range. Additionally, the phase dispersion obtained caused fractionated crystallization phenomena in both phases.

Keywords : Polymer blend; Biodegradable polymers; Polydioxanone; Polycaprolactone; Compatibilization.