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Description
Poly(L-lactic) acid (PLLA) is a biodegradable and biocompatible thermoplastic polyester and an excellent candidate to replace traditional petroleum-based polymers in a wide spectrum of applications [1]. However, its poor mechanical and barrier properties, thermal stability and low crystallization rate render it slightly inferior to conventional thermoplastics. Tailoring the properties of PLLA through the targeted incorporation of nanofillers is a common approach to overcome these issues [2,3].
PLLA is semicrystalline with α crystal-form being the most common [1]. Upon industrial processing conditions the metastable and conformationally disordered α΄phase can be formed, which transforms to α phase upon heating [1].
Within this work, PLLA/TiO2 nanocomposites, were prepared in a twin-screw extruder in six different concentrations in TiO2. Samples of all concentrations were crystallized from the melt at 85°C and 130°C, where the formation of α΄ and α phase, is respectively favored. The melting behavior and crystallinity are investigated by Differential Scanning Calorimetry and the crystalline structure through X-ray Diffraction. Crystallization behavior and crystal morphology are investigated by means of Polarising Optical Microscopy. Raman scattering is employed to identify the chain packing and conformations of the crystalline forms, while Broadband Dielectric Spectroscopy is employed for the dielectric characterization of the bionanocomposites. Results are compared in terms of the effects of the added presence of the nanofiller and the crystallization temperature, on the properties of the bionanocomposites and are expected to give valuable feedback towards the development of new multifunctional biomaterials with superior properties.
[1] Di Lorenzo ML, Androsch R, Polym Int 68(3): 320-334, 2019.
[2] Kaseem M, Hamad K, Ur Rehman Z, Materials 12(22): 3659, 2019.
[3] Zavvou EE et al., Mod Concept Material Sci. 3(5), 2021. MCMS. MS.ID.000572.
| Speaker Country | Greece |
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