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Current progress on biobased thermosetting epoxy focuses on developing high thermomechanical properties. However, its functional applications that represent a significant subject for future trends ...

A range of fully biobased unsaturated polyesters (bio-UPs) derived from 2,5-furandicarboxylic (FDCA), itaconic acid (IA), succinic acid (SA), and 1,3-propanediol (PD) were obtained via direct polycondensation. The chemical structures of the bio-UPs were identified by Fourier transfrom infrared spectroscopy and 1H NMR before they were cured together with a biobased, nonvolatile reactive diluent, guaiacol methacrylate (GM). The thermal and mechanical characterizations of the cured bio-UPs were evaluated using thermogravimetric analysis, 3-point bending tests, and dynamic mechanical analysis. Results showed that the thermal properties, flexural strength, and modulus of the cured bio-UPs were greatly improved after the introduction of FDCA. The temperature of 5% thermal weight loss reached 330 °C, and the flexural strength and modulus reached 122.8 and 3521 MPa, respectively. These results indicate that the bio-UPs have the potential to replace petroleum-based UPs.

Epoxidized citric acid (ECA) is synthesized as a highly reactive bio-based compatibilizer to improve the flexural property of polylactide (PLA)/microcrystalline cellulose (MCC) blends. Confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analysis, ECA includes three oxirane groups in its chemical structure with the rather high epoxy value at 0.76. After adding 1–5 wt % ECA in PLA/MCC blends, the interfacial adhesion between PLA and MCC is significantly improved. Accordingly, flexural strength, flexural modulus as well as impact strength of PLA/MCC/ECA blends are all improved and thus the increase of the flexural properties. This work suggests an effective way to create biobased compatibilizer with high reactivity and hereby displays a feasible way to fabricated fully bio-based PLA/MCC blends with high performance.

A biobased monofunctional compatibilizer (called Epicard) is first synthesized by the reaction of cardanol with epichlorohydrin as confirmed by Fourier transform infrared and 1H NMR. Subsequently, biosourced polymers, polylactide (PLA) and starch, are melt-blended by a twin-screw extruder with Epicard. Confirmed by the measurements of contact angle and 1H nuclear magnetic resonance of the extracted starches from PLA/starch/Epicard blends, the Epicard only possesses a monoepoxy group to mainly react with starch and then increased the hydrophobicity of the starches during the melt-blending process. As a result, an obvious improvement to the interfacial adhesion between starch and PLA is observed by the scanning electron microscopy. Furthermore, the tensile properties of PLA/starch blends are effectively improved with the addition of Epicard. This study suggests a simple but effective material technique by utilizing a novel plant oil modifier to increase interfacial adhesion in fabricating fully biobased PLA...