Facile synthesis and characterization of activated star-shaped itaconic acid based thermosetting resins

Novel star-shaped thermosetting resins were synthesized by condensation-reaction of itaconic acid and glycerol, followed by treatment of the oligomers, by methanol and allyl alcohol. Employing 1H and 13C NMR and FT-IR, the chemical structures of the resins were studied. The thermomechanical properties were evaluated by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Viscometry and thermogravimetric analyses (TGA) were also employed to study the rheological and thermal properties of samples. The viscosity of the methanol-treated resin was 4.2 Pa s at 25 °C, which dropped to 0.25 Pa s at 70 °C. The allyl alcohol-treated resin showed a lower viscosity (1.8 Pa s at room temperature, and 0.14 Pa s at 70 °C). A substantially higher glass temperature (Tg) was recorded for methanol-treated resin (150 °C) compared to that of the allyl alcohol-treated resin (93 °C). Compared to the allyl alcohol-treated resin, very good mechanical properties for the methanol-treated resin was achieved, in terms of storage modulus, (61% higher G′). Excellent environmental profile (i.e. high biobased contents and biodegradability), inexpensive raw materials, along with promising rheological and thermomechanical properties are advantages of these novel resins, which make the resins comparable with, and superior in some aspects, to other thermosetting systems.