Catalytic Transesterification of Starch with Plant Oils: A Sustainable and Efficient Route to Fatty Acid Starch Esters

Abstract

The transesterification of maize starch with olive oil or high oleic sunflower oil was studied under homogeneous conditions in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst. Most importantly, this method used two renewable resources directly, without any pretreatment or derivatization, for the synthesis of polymeric materials with desirable properties. Moreover, the solvent, oils, and catalyst could be recovered through facile work-up and reused for further modifications. The obtained fatty acid starch esters (FASEs) were highly soluble in common organic solvents and were thoroughly characterized. Degrees of substitution (DS) were calculated using P NMR spectroscopy, and DS values of approximately 1.3 were obtained. Differential scanning calorimetry analysis revealed thermal transitions of the modified starches at approximately 80-90 °C. Films were produced from these FASEs, and their hydrophobic surfaces were characterized using contact-angle measurements. Furthermore, mechanical properties were examined using tensile strength measurements and showed approximately 40 and 80 % elongation at break for modified maize starch and modified amylose from maize, respectively.

Recent Advances in the Preparation and Characterization of Intermediately to Highly Esterified and Etherified Starches: A Review

“…However, the reagents mentioned above may still impose toxicity or are difficult to remove from modified starch. In recent studies, DMSO in mixture with basic salts or lipase enzymes, has been researched. However, removing DMSO from a final starch product is still uneconomical in industrial scale due to its high hygroscopicity and low volatility .…”

Rheological and mechanical properties of cellulose/LDPE composites using sustainable and fully renewable compatibilisers

“…Cellulose characterization is provided in the Supporting Information (Figure S1–S2). The transesterified amylose or starch were prepared according to a recent publication by Meier et al . using high oleic sunflower oil provided by Cargill (94.5% of acid chains were unsaturated, with 88.7% being monounsaturated, i.e., oleic acid, as determined by 1 H NMR) and maize starch purchased in a local supermarket.…”

“…1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (98%, Aldrich) and dimethyl sulfoxide (anhydrous, > 99.9%, Aldrich) were used as received. These polymeric materials have been previously characterized in detail and showed a glass transition temperature ( T g ) at 90 °C while no T m was observed prior to their decomposition from 270 °C onwards.…”

“…Herein, we report on the use of new renewable compatibilisers for the preparation of cellulose‐reinforced low‐density PE (LDPE) composites. These compatibilisers are based on starch and amylose, branched structural analogues of cellulose [Scheme (a)], which are transesterified using high oleic sunflower oil to attach fatty acid chains onto its hydroxy groups [Scheme (b)], as reported in a previous publication . In this catalytic process, a processable polymeric material is obtained, combining the hydrophilicity of a glucose repeat unit along the main chain with the hydrophobicity of a fatty acid side chain.…”

“…(a) Structures of cellulose and starch with key parameters of their structure, (b) synthesis of amylose‐ or starch‐based compatibiliser using high oleic sunflower oil, and (c) the preparation of composites using LDPE, bulk cellulose, and the renewable compatibilisers prepared according to Meier et al . [Color figure can be viewed at wileyonlinelibrary.com]…”