PREPARATION AND CHARACTERIZATION OF POLYSTYRENE/STARCH BLENDS FOR PACKAGING APPLICATIONS

MARTÍN BERRUEZO; LEANDRO LUDUEÑA; EXEQUIEL S. RODRIGUEZ; VERA A. ALVAREZ

JOURNAL OF PLASTIC FILM & SHEETING

SAGE PUBLICATIONS LTD

Año: 2014 vol. 30 p. 141 - 161

8756-0879

Polystyrene/thermoplastic starch blends from 90/10 to 50/50 (w/w) were preparedby melt blending. Blends were characterized by scanning electron microscopy(morphology); thermogravimetric analysis (thermal stability and weightcontent of each component); Fourier transform infrared spectroscopy (identificationof functional groups); differential scanning calorimetry (thermal properties);tensile tests (strength, modulus, elongation at break and tenacity) and biodegradationin soil (biodegradability). The biodegradation process was also followed bythermogravimetric analysis calculating the loss of each component after removingthe samples from soil at different time intervals. Scanning electron microscopyresults showed good starch dispersion in the blend. The Fourier transform infraredspectroscopy analysis suggested that only physical interaction took placebetween the polystyrene and the thermoplastic starch. The tensile tests revealeda considerable decrease in the mechanical properties of the polystyrene-thermoplasticstarch blends as a function of the thermoplastic starch content. The 50/50blend showed decreases of 48% in the Young?s modulus, 62% in the tensilestrength and increases of 62% in the elongation at break, in comparison to neatpolystyrene. The biodegradability tests showed that the greater the thermoplasticstarch concentration in the blend, the faster the mass loss, which was also confirmed by the thermogravimetric analysis and Fourier transform infrared spectroscopyanalysis.