Effects of Starch Acetylation on Application of Thermoplastic Starch as Packaging Material : Degree of substitution, Gelatinization and Biodegradability
Thermoplastic starch (TPS), despite its environmental advantages, suffers from brittleness and poor processability due to extensive hydrogen bonding in native starch. This study aimed to characterize the relationship between gelatinization behavior and plasticization of acetylated starch and to evaluate the biodegradability of acetylated-TPS (ATPS). Native corn starch was acetylated to three different degrees of substitution (DS = 0.020, 0.087, 0.117). FT-IR spectra confirmed successful acetylation with the appearance of C=O stretching peaks at 1726 cm-1, and XRD patterns showed decreased crystallinity as DS increased. Water solubility and swelling power increased from 4.985% and 4.935 g/ g (Native starch) to 10.054% and 9.983 g/g (DS 0.117) respectively, indicating enhanced water accessibility. Differential scanning calorimetry revealed a reduction in gelatinization temperature from 71.49oC to 64.80oC and gelatinization enthalpy from 2.925 J/g to 1.777 J/g. These changes suggest improved plasticizer penetration during thermal processing. In disintegration tests under home composting conditions, A-TPS (AS 0.117) film showed greatly faster degradation rate than that of TPS and reached over 90% of degradation within one week. The results indicate that starch acetylation effectively enhances the plasticization level of A-TPS, and its improved biodegradability confirms the potential to broaden the applicability of A-TPS in sustainable packaging materials.
목차
Abstract Introduction Materials & Methods 1. Materials 2. Starch acetylation 3. Characterization of acetylated starch 4. Assessment of disintegration behavior of acetylated-TPS Results & Discussion 1. Chemical structure 2. Crystalline structure 3. Water solubility and swelling power 4. Thermal properties 5. Disintegration of A-TPS casting films in home composting condition Conclusions Acknowledgement References