Thermoplastic starch composites with TiO2 particles: Preparation, morphology, rheology and mechanical properties

• Published in: International journal of biological macromolecules 2017-08, Vol.101, p.273-282
• Main Authors: Ostafińska, A., Mikešová, J., Krejčíková, S., Nevoralová, M., Šturcová, A., Zhigunov, A., Michálková, D., Šlouf, M.
• Format: Article
• Language: English
• Subjects: Morphology; Thermoplastic starch; Titanium dioxide particles
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2017.03.104

•A reliable preparation of thermoplastic starch (TPS) composites is introduced.•The method consists in solution casting followed by melt mixing (SC+MM).•TPS/mTiO2 composites prepared by SC+MM method are very homogeneous.•The increase in dynamic moduli for TPS/mTiO2(3%) composite exceeded 40%. Composites of thermoplastic starch (TPS) with titanium dioxide particles (mTiO2; average size 0.1μm) with very homogeneous matrix and well-dispersed filler were prepared by a two-step method, including solution casting (SC) followed by melt mixing (MM). Light and scanning electron microscopy confirmed that only the two-step procedure (SC+MM) resulted in ideally homogeneous TPS/mTiO2 systems. The composites prepared by single-step MM contained non-plasticized starch granules and the composites prepared by single-step SC suffered from mTiO2 agglomeration. Dynamic mechanical measurements showed an increase modulus with increasing filler concentration. In TPS containing 3wt.% of mTiO2 the stiffness was enhanced by >40%. Further experiments revealed that the recommended addition of chitosan or the exchange of mTiO2 for anisometric titanate nanotubes with high aspect ratio did not improve the properties of the composites.