Characterization of Glycerol and Aloe Vera as Plasticizer in Polyethylene/Starch-Based Film

Abstract

The combination of starch (S) and polyethylene (PE) increased the mechanical properties of starch and improved the degradation ability of PE. However, the polyethylene-starch (PE-S) combination has inconsistent mechanical properties performance. Therefore, the objective of this paper was to investigate the PE-S-based film’s characterization changes and mechanical properties performance upon the addition of different types and formulations of a plasticizer; 30% glycerol, 30% aloe Vera (AV) gel, or a combination of 30% glycerol with 1% AV powder. First, a Banbury mixer was applied to prepare the resin, followed by a hot-pressed technique to obtain a thin film. Glycerol acted as a plasticizer disturbed the functional group appearance of PE-S-based film. Thus, it reduced the tensile strength and elongation at break performance, including increased the water absorption of the film. The results also revealed that an apparent agglomeration of starch appeared in PE-S film upon adding 30% AV gel at once, showing the most deficient mechanical properties with the highest water absorption occurred. Surprisingly, the combination of 30% glycerol with 1% AV powder suggests 1% AV powder acted as a crosslinker between starch and glycerol because the tensile strength increases by 49% compared to PE-S with 30% glycerol only. Furthermore, the crystallinity percentage of PE-S film reduced upon adding other materials from 54.04% to between 39.90% until 43.93%. In conclusion, the type and percentage of AV played an essential role in PE-S film, either acting as a plasticizer or a crosslinker.