Abstract:
The influence of carboxylic acids on the mechanical properties of TPS produced by
spray drying have been investigated. Both malic acid and citric acid (polycarboxylic
acids) were used as plasticizer. Starch was spray-dried from solution to prepare
amorphous TPS dog bones by compression molding.
X-ray Diffraction (XRD) results showed that all the freshly solution spray dried TPS
powder and dog-bones samples were amorphous irrespective of the amount of
plasticizer added. Scanning Electron Microscope (SEM) was used to examine the
morphology of solution spray dried TPS powder. No noticeable difference was
observed on the morphology between the samples. Particles were spherical and
homogenous surface was observed. The FT-IR analysis indicated the interaction of
plasticizers with starch chains by hydrogen bonding. In TGA analysis, apart from
moisture loss at 100oC, samples were thermally stable up to 170oC temperature.
Tensile testing showed that Malic Acid plasticized samples exhibited a more elastic
behavior as compared to Citric Acid plasticized samples. Whereas, the quantity of the
plasticizers and tensile strength of TPS dog-bones was inversely proportional to each
other.
