Soybean and coconut oil based unsaturated polyester resins: Thermomechanical characterization

• Coconut oil was used for the first time to prepare UPRs.
• New UPRs with high thermal stability were obtained.
• Soybean oil based UPRs showed the best thermomechanical properties.

This paper reports the development of new unsaturated polyesters resins (UPRs) based on soybean oil and coconut oil. Unsaturated polyesters (UPs) were firstly synthesized by polycondensation from renewable monomers and were further crosslinked using styrene. The chemical structure of the new UPs was confirmed by attenuated total reflectance Fourier Transform Infrared (ATR-FTIR) and by proton Nuclear Magnetic Resonance (1H NMR) spectroscopies. The thermal and mechanical properties of the UPs and UPRs were studied by thermogravimetric analysis (TGA) and by dynamic mechanical thermal analysis (DMTA) to evaluate the impact of the incorporation of renewable monomers in the properties of the materials. TGA analysis revealed that bio-based UPs are thermally stable until temperatures of 250 °C. The Tg values obtained for these new UPs varied between −11 °C and 2 °C, being the UP composed by bio-based soybean oil and propylene glycol the resin with the highest Tg. As expected, after crosslinking UPRs showed to be thermally more stable than the UPs. The DMTA analysis revealed that the E' and the Tg could be easily tailored by varying the monomers in the formulation.

Figure optionsDownload as PowerPoint slide