Bio-Based Epoxy Resins Based on Linseed Oil Cured with Naturally Occurring Acids

Area of Science:

• Polymer Science
• Materials Chemistry

Background:

• Epoxy resins are versatile polymers with broad industrial applications.
• Developing sustainable alternatives to petroleum-based epoxy resins is crucial for environmental impact reduction.

Purpose of the Study:

• To investigate the structural properties of epoxidized linseed oil (ELO) based resins.
• To optimize resin properties by varying hardener components and ELO mass.
• To explore bio-based alternatives for petroleum-derived hardeners.

Main Methods:

• Synthesized ELO-based epoxy resins with varying molar ratios of methyltetrahydrophthalic anhydride (MTHPA), pyromellitic dianhydride (PMDA), and maleic acid (MA).
• Determined gel time and Shore A/D hardness for different formulations.
• Investigated the effect of ELO mass (8-16 g) while keeping hardener systems constant.
• Substituted PMDA with oxalic acid and citric acid to create bio-based resins.

Main Results:

• The optimal MTHPA/PMDA/MA molar ratio of 8/1/8 yielded the shortest gel time (0.9 min) and highest hardness (Shore A 85, Shore D 34).
• Increasing ELO mass prolonged gel time, but hardness remained consistent up to 14 g ELO.
• Replacing PMDA with oxalic or citric acid resulted in shorter gel times and maintained hardness in the new bio-based epoxy resins.

Conclusions:

• The study successfully characterized ELO-based epoxy resins and identified optimal formulations for specific properties.
• The findings demonstrate the potential of utilizing bio-based compounds to create sustainable epoxy resins without compromising performance.
• This research contributes to the development of greener materials in the polymer industry.