Erucic acid-based alkyd–acrylic hybrid copolymers: Synthesis, characterization, and coating applications

This investigation examines the preparation and characterization of alkyd-acrylic hybrid copolymers obtained from erucic acid obtained from mustard oil, aiming to develop a sustainable alternative to traditional petroleum-based coating materials. An alkyd macromer was synthesised from phthalic anhydride, glycerol, and erucic acid, followed by copolymerisation with butyl acrylate (BA) and methyl methacrylate (MMA) in different ratios. Structural confirmation of both macromer and copolymer formation was compared through FTIR with a strong ester carbonyl peak at 1720 cm −1 and 1 H NMR spectroscopy, with the disappearance of vinylic peak at 5.8 ppm confirming successful polymerisation. Thermal analysis using TGA demonstrated an enhancement in thermal stability of copolymers containing higher alkyd content, showing an increase from 385.8 to 392.6℃. This improvement is primarily due to the presence of aromatic components and increased crosslinking density within the polymer network. DSC analysis showed a single, broad glass transition temperature for each sample, demonstrating the formation of homogeneous, amorphous copolymer films. The T g values exhibited a gradual increase from 62.6 to 104.5℃, with rising MMA content. DLS revealed bimodal particle size distributions, with particle populations spanning approximately 22–190 nm. SEM showed that optimized macromer/MMA/BA compositions significantly influenced the surface morphology, highlighting the combined impact of alkyd and acrylate content on the resulting material morphology. Overall, the findings demonstrate that erucic acid-based alkyd-acrylic copolymers possess well-balanced physicochemical and mechanical properties, underscoring the suitability of alkyd-MMA-BA-based copolymers for diverse applications, highlighting their potential as high-performance coating materials.