Adipic acid – glutaric anhydride – epoxidised linseed oil biobased thermosets with tunable properties

Abstract

Article:Matharu, Avtar Singh orcid.org/0000-0002-9488-565X, Ding, Cheng and Tian, Guangmao ABSTRACTIn this study, the preparation and characterization of biobased thermosets comprising epoxidized linseed oil (ELO), adipic acid and/or glutaric anhydride, initiated by N,N-4-dimethylaminopyridine (DMAP) is reported. By changing the ratio of adipic acid to glutaric anhydride, the obtained resins changed from soft and flexible to hard and brittle materials. The Young's modulus varied from 25 MPa to 1477 MPa, tensile strength varied from 10.3 MPa to 25.7 MPa, and the elongation at break varied from 2.7% to 67.5%. The maximum toughness was found with the sample containing 20% glutaric anhydride and 80% adipic acid. With the increase of glutaric anhydride content, the total heat released during the curing reaction and the glass transition temperature (T g ) increased. This is the first paper that reports the combination of glutaric anhydride and adipic acid as curing agents for epoxidized plant oils to produce thermosets ranging from flexible to hard.

Curing of epoxidized linseed oil: Investigation of the curing reaction with different hardener types

“…The absorption bands around 3500 cm −1 , which represent the stretching vibrations of OH groups, increase with increasing curing time. This indicates that epoxy groups were ring‐opened with carboxylic acid groups, where new hydroxyl groups are formed 37,38 . The absorption band at 3050 cm −1 decreases with increasing curing time.…”

“…This indicates that epoxy groups were ring-opened with carboxylic acid groups, where new hydroxyl groups are formed. 37,38 The absorption band at 3050 cm −1 decreases with increasing curing time. It represents the CH stretching of the methylene group of the epoxide ring and hence the ring opening reaction.…”

Building thermally and chemically reversible covalent bonds in vegetable oil based epoxy thermosets. Influence of epoxy–hardener ratio in promoting recyclability

“…There is scarce information regarding EVO curing with dicarboxylic acids. [7][8][9][10][11][12][13] However, an important aspect of the epoxy/acid reaction is the formation of b-hydroxyesters that are responsible for transesterification reactions, which allow the recyclability of the polymeric networks. 14,15 Another reaction favouring network chain reorganization is the metathesis of disulfide covalent bonds by a dynamic exchange in the main or side chains, usually triggered by external stimuli, such as pressure or temperature, known as the disulfide exchange reaction.…”

Kinetical Study, Thermo-Mechanical Characteristics and Recyclability of Epoxidized Camelina Oil Cured with Antagonist Structure (Aliphatic/Aromatic) or Functionality (Acid/Amine) Hardeners

“…However, very few studies have been published regarding the mix of hardeners. Ding et al [ 23 ] prepared bio-based thermosets by curing ELO with adipic acid/glutaric anhydride catalyzed by N, N-4-dimethylaminopyridine (DMAP), with the properties being modulated depending on the ratio of the two hardeners. Williams et al [ 24 ] synthesized vitrimers from DGEBA with citric acid (CA)/sebacic acid (SA) by adding a small amount of n-alkylamine.…”