Dual Plasticizer/Thermal Stabilizer Effect of Epoxidized Chia Seed Oil (Salvia hispanica L.) to Improve Ductility and Thermal Properties of Poly(Lactic Acid)

Abstract

The use of a new bio-based plasticizer derived from epoxidized chia seed oil (ECO) was applied in a poly(lactic acid) (PLA) matrix. ECO was used due to its high epoxy content (6.7%), which led to an improved chemical interaction with PLA. Melt extrusion was used to plasticize PLA with different ECO content in the 0–10 wt.% range. Mechanical, morphological, and thermal characterization was carried out to evaluate the effect of ECO percentage. Besides, disintegration and migration tests were studied to assess the future application in packaging industry. Ductile properties improve by 700% in elongation at break with 10 wt.% ECO content. Field emission scanning electron microscopy (FESEM) showed a phase separation with ECO content equal or higher than 7.5 wt.%. Thermal stabilization was improved 14 °C as ECO content increased. All plasticized PLA was disintegrated under composting conditions, not observing a delay up to 5 wt.% ECO. Migration tests pointed out a very low migration, less than 0.11 wt.%, which is to interest to the packaging industry.

Comparative Study of the Properties of Plasticized Polylactic Acid with Maleinized Hemp Seed Oil and a Novel Maleinized Brazil Nut Seed Oil

“…Both plasticizers, MBNO and MHO, decrease the T g and T cc of PLA, which is indicative of an increase in the mobility of the polymer chains at lower temperatures, evidencing the plasticizing effect of both maleinized oils [ 45 ]. The same evolution was reported by Dominguez-Candela et al [ 46 ], who employed epoxidized chia oil (ECO) in PLA. On the other hand, no significant variations were observed in T m , showing that after the addition of the plasticizers, the T m remained at values around 150–153 °C for all the samples.…”

Expanding Poly(lactic acid) (PLA) and Polyhydroxyalkanoates (PHAs) Applications: A Review on Modifications and Effects

“…Dominguez-Candela and co-authors [ 70 ] have reported a new biobased PLA plasticizer derived from Epoxidized Chia Seed Oil (ECO). PLA with various contents of ECO (0–10 wt.%) was prepared using melt extrusion.…”

Improved Mechanical, Thermal, and Hydrophobic Properties of PLA Modified with Alkoxysilanes by Reactive Extrusion Process

“…However, the degree of disintegration was delayed by only 14 days. In another work, Dominguez-Candela et al [54] reported an increase of more than 53% in PLA crystallinity when introducing an organic bio plasticizer, but, a disintegration of more than 90%, which is considered by the UNE 20,200 standard as a biodegradable material, was obtained only 3 days later. Therefore, in view of the previous results, and given that in the present study, there is only a 10.6% increase in crystallinity concerning neat PLA, it can be affirmed that a subsequent disintegration process would be practically unaffected, considering the PLA modified by REX as totally biodegradable.…”

“…M specifically, PLA samples modified with low alkoxysilane concentrations, O-PLA-A a P-PLA-A, displayed similar thermal stability to neat PLA, breaking down at temperatu around 364-362 °C, whereas higher organosilane contents showed slightly lower deco position temperatures (356-358 °C). As evidenced by 1H-NMR and SEC analyses, th small changes may be associated with ester-alkoxysilane exchange reactions, which curs at high temperature, causing chain scissions via C-H hydrogen transfer reactio [36,[54][55][56][57]. Consequently, lower molar weights and, therefore, lower thermal stabilit were obtained compared to neat PLA.…”