Effects of Plasticizers on Mechanical Properties, Oxygen Permeability, and Microstructural Characteristics of HPMC/Beeswax Composite Film

The ability to plasticize Hydroxypropyl Methyl Cellulose/Beeswax (HPMC/BW) composites depends on plasticizers and their concentration. This paper conducted studying on the impacts of plasticizers to HPMC/BW properties. The plasticizers were used in this research included Glycerol (G), Propylene Glycol (PG), and Polyethylene Glycol 400 (PEG 400) which had the concentration changed in range of 1-3%. HPMC/BW composite films incorporated with 2% of plasticizers formed films with the best characteristics among three tested concentration. Tensile strength and elastic modulus of films were decreased when adding plasticizers, whereas elongation at break were increased. Therefore, it caused an increase in oxygen permeability of HPMC/BW films in comparison with the control film. However, Glycerol showed the lowest Oxygen Permeability (OP) values compared to other composite films. The films were evaluated its microstructural quality using method of scanning electron microscopy (SEM) which had the effects of plasticizers and their efficiencies of plasticizing polymer networks.