Mechanical and rheological properties of epoxidized soybean oil plasticized poly(lactic acid)

Abstract

Poly(lactic acid) (PLA) is a well known biodegradable thermoplastic with excellent mechanical properties that is a product from renewable resources. However, the brittleness of PLA limits its general applications. Using epoxidized soybean oil (ESO) as a novel plasticizer of poly (lactic acid), the composite blend with the twin-screw plastic extruder at five concentrations, 3, 6, 9, 12, and 15 wt %, respectively. Compared with pure PLA, all sets of blends show certain improvement of toughness to different extents. The concentration with 9 wt % ESO increases the elongation at break about 63%. The melt flow rates of these blends with respect to different ESO ratio have been examined using a melt flow indexer. Rheological behaviors about shear viscosity and melt strength analysis are discussed based on capillary rheology measurements. The tensile strength and melt strength of the blends with 6 wt % ESO simultaneity reach the maximums; whereas the elongation at break of the blends is the second highest level. ESO exhibits positive effect on both the elongation at break and melt strength. The results indicate that the blend obtained better rheological performance and melt strength. The content of 6 wt % ESO in PLA has been considered as a better balance of performance. The results have also demonstrated that there is a certain correlation between the performance in mechanical properties and melt rheological characterization for the PLA/ESO blends.

Tensile Properties of Durian Skin Fibre Reinforced Plasticized Polylactic Acid Biocomposites

“…This finding can be explained by the theory of gelation where the presence of the plasticizer weakened the polymer structure thus improves the flexibility of the PLA biopolymer [8]. The low weight of molecular plasticizer molecules reduced and disrupted the polymers interaction which makes the polymer chain hold together [9][10].…”

Comparative Study of Chemical, Mechanical, Thermal, and Barrier Properties of Poly(Lactic Acid) Plasticized with Epoxidized Soybean Oil and Epoxidized Palm Oil

“…With schematic diagram of interaction provided, the compatibility and interaction between PLA and epoxidized plant oils was proposed to be from the hydrogen bonding between terminal hydroxyl groups of PLA and the oxirane groups of the EPO (Al-Mulla et al 2010) and ESO (Xu and Qu 2009). …”

“…Research on utilizing plant oils as plasticizers, including studies of rubber seed oil, neem oil, Madhuca oil, olive oil, corn oil, castor oil, soybean oil, and palm oil, have been picking up recently (Liu et al 2006;Gamage et al 2009;Xu and Qu 2009;Al-Mulla et al 2010;Chua et al 2012;Xiong et al 2013). The benefits of these alternative plasticizers are definitely lower toxicity (Fenollar et al 2009), good lubricity, lower volatility, (Lathi and Mattiason, 2007), low cost, renewable nature, and biodegradability (Wang et al 2013).…”

Poly(Lactic Acid) as a Biopolymer-Based Nano-Composite

“…Thermal and scanning electron microscope analysis revealed that epoxidized soybean oil is partially miscible with PLA. Rheological and mechanical properties of PLA/epoxidized soybean oil blends were studied by Xu and Qu (2009) Epoxidized soybean oil exhibited a positive effect on both the elongation at break and melt rheology. Al-Mulla et al (2010b) also reported that plasticization of PLA (epoxidized palm oil) was carried out via solution casting process using chloroform as a solvent.…”