Characterization of environmentally friendly polymers by inverse gas chromatography: I amylopectin

Amylopectin, as a potato starch based polymer, with a molecular weight of six million gram/mol was characterized using the Inverse Gas Chromatography Method (IGC). DSC method was also used to measure the glass and melting temperatures. Both DSC and IGC agreed well on a T-g of 105 degrees C and T-m of 160-166 degrees C. Nineteen solutes (solvents) were injected onto a chromatographic column containing amylopectin. These solutes revealed the interaction of alkanes with AP, and the wettability and water intake of AP. Alkanes showed exothermic values of interaction parameters which were increased as the temperature increased and as the number of carbons in the alkane series decreased. Retention diagrams of these solutes in a temperature range of 80-200 degrees C revealed two zones, crystalline and amorphous. T-g and T-m were measured using these zones which complimented the DSC values. The two zones were used to calculate the degree of crystallinity below the melting temperature which ranged from 85% at 104 degrees C to 0% at 161 degrees C. The dispersive component of the surface energy of amylopectin was measured using alkanes which ranged from 25.35 mJ/m(2) stop at 80 degrees C to 8.47 mJ/m(2) stop at 200 degrees C. This is attributed to the weak crystalline surface of AP at 80 degrees C and when the surface melted at 160 degrees C the surface energy decreased due to the thermal expansion of the surface.