Comparison Of Tensile Strength And Water Absorption Properties Of Pva /Sago Starch And Pva/ Sago Starch Acetate
Biodegradable plastic utilizing sago starch blended with PVA are fabricated and characterized in this study.
PVA/sago starch and PVA/sago starch acetate system was prepared via casting method and starch acetate having degree of
substitution (DS) 0.30 was prepared by acetylation process. The different percentage ratios of 50 to 90% of sago starch (SS)
and sago starch acetate (SSA) for PVA blends were hot solution casted and mechanical properties, water absorption properties
and transition temperature blends were observed. From water absorption analysis up to 10days, weight gains were observed for
all blends as they are hydrophilic and highly absorb water. All samples showed rapid increase in weight gain at initial
hydration. Higher water absorption were obtained with PVA/SSA as compared to PVA/ SS with percent water absorption
between 35 to 60% for PVA/SS and 15 to 44% at room temperature. PVA/SSA blend had increased the hydrophobicity of
starch and reduces swelling power of film. From DSC thermogram performed, the highest gelatinization temperature were
obtained by the composition of 20% PVA / 80% SS of 241ºC. PVA/SSA with 50%PVA/50%SA ratios had gelatinization
temperature of 208 ºC. The difference in gelatinization temperature indicated differences in the perfection of starch crystals.
The higher the gelatinization temperature, crystals are more perfect in the crystal lattice. Generally, PVA/SSA blend have
higher Tensile strength compared to PVA/SS for all preparations. Higher SSA content also increases the modulus and
improved rigidity. Microscopy images also showed better dispersion and homogeneity of PVA/SSA compared to PVA/SS.
Hence PVA/SSA using modified sago starch has improved mechanical and better resistant to water.
Index Terms- Polyvinyl alcohol, Sago starch, Sago starch acetate, Tensile, Water absorption.