17-hydroxy oleic acid as precursor for unsaturated and epoxy fatty acid estolides: application as plasticizers in poly(3-hydroxybutyrate) films

Authors: Ashby, Richard - Rick; Solaiman, Daniel

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Estolides (oligomeric fatty acid esters) have been known for close to a century but only within the last few years have they been efficiently produced with control over molecular structure. While estolides are commonly associated with lubricant applications, they can also be beneficial as plasticizing agents in polymer matrices. Our research group has produced unique unsaturated and epoxy estolide molecules from 17-hydroxy oleic acid derived from sophorolipids and applied those estolide molecules as plasticizers for poly(3-hydroxybutyrate) (PHB) polymer films. The presence of estolides in the PHB film matrix reduced the melting temperatures (Tm) and glass transition temperatures (Tg) of the PHB films while the %-crystallinities remained relatively constant (±2.0%). The presence of estolides also influenced the tensile properties of the films by decreasing their tensile strength and moduli while increasing their elongation. Curing the films for 3 months elicited an enhanced tensile strength and modulus when compared to the initial films at the same estolide concentration. Irradiation was used in an attempt to crosslink the estolides however, the result was a reduction in molecular weights (by up to 81%) which further reduced the tensile strength, elongation and modulus of the PHB films. While the strength of the PHB films declined in the presence of both estolides, the plasticity and elongation improved validating that these unique SL-derived estolides can effectively serve as plasticizers in PHB films.