Jinyue Dai

Polyesters derived from itaconic acid for the properties and bio-based content enhancement of soybean oil-based thermosets

A series of bio-based polyesters were synthesized by melt polycondensation of itaconic acid with diols and glycerol without VOC emission. Their chemical structures were confirmed by FT-IR and 1H-NMR before they were made to copolymerize with acrylated epoxidized soybean oil (AESO). The thermal and mechanical properties of the resulting thermosets were investigated by differential scanning calorimetry (DSC), tensile testing and dynamic mechanical analysis (DMA). Their coating properties on tinplate and glass plate were also studied. Results showed that the tensile strength, modulus, glass transition temperatures and bio-based content of the AESO-based thermosetting resins were significantly improved after the introduction of the synthesized polyesters. In addition, the modified AESO systems could be well coated on the surface of tinplate and glass plate and good coating properties such as hardness, flexibility, adhesion, solvent resistance and water absorption were demonstrated. They showed great potential for applications as coatings, adhesives and composites.

Diisocyanate free and melt polycondensation preparation of bio-based unsaturated poly(ester-urethane)s and their properties as UV curable coating materials

This paper reported the synthesis of bio-based unsaturated poly(ester-urethane)s via a nonisocyanate route, by metal-catalyzed melt polycondensation of itaconic acid with urethanediols. Three novel types of bio-based unsaturated poly(ester-urethane)s, namely, poly(urethanediol 2-itaconic acid), poly(urethanediol 4-itaconic acid) and poly(urethanediol 6-itaconic acid) (poly(U2-IA), poly(U4-IA) and poly (U6-IA) for short code, respectively), were prepared by a green synthetic route. The urethane linkage was formed by the reaction of two equivalent of ethylene carbonate with 1,6-hexanediamine, 1,4-butanediamine and 1,2-ethanediamine to form urethanediols. The urethanediols underwent polymerization with itaconic acid (IA) in the presence of metal catalyst dibutyltin dilaurate (DBTL) to produce low-molecular-weight bio-based unsaturated polyurethanes. Then, these bio-based unsaturated poly(ester-urethane)s were formulated with free radical photoinitiator and curing promoter to prepare UV curable polyurethane systems. After UV curing, the tensile properties, thermal properties and general coating properties of the three UV-cured polyurethane films were similar to that of UV cured polyurethane films prepared by polyurethane-acrylate (PUA). The results suggested that the obtained bio-based unsaturated polyurethanes could serve as coating materials.

Synthesis of eugenol-based multifunctional monomers via a thiol–ene reaction and preparation of UV curable resins together with soybean oil derivatives

Two kinds of UV-curable monomers (EM2G and EM3G) were synthesized from eugenol via a thiol–ene reaction. Their chemical structures were confirmed by FT-IR, 1H-NMR and 13C-NMR before they were employed to copolymerize with acrylated epoxidized soybean oil (AESO). Bio-based UV curable resins were prepared and their thermal and mechanical properties were investigated by tensile testing and dynamic mechanical analysis (DMA). Their coating properties on tinplate were also studied. The results showed that the tensile strength, tensile modulus and glass transition temperatures of the cured AESO were significantly improved after the introduction of eugenol-based monomers. In addition, the UV-cured resins could be well coated on the surface of tinplate and good coating properties, such as hardness, flexibility, adhesion, solvent resistance and water absorption were demonstrated.

Biobased Benzoxazine Derived from Daidzein and Furfurylamine: Microwave-Assisted Synthesis and Thermal Properties Investigation

A biobased benzoxazine resin (Dz-f) demonstrating excellent thermal properties was synthesized from daidzein and furfurylamine by using a microwave heating method. The chemical structure of synthesized benzoxazine monomer was identified by FTIR and NMR (1 H and 13 C NMR) before it was cured and its thermal properties evaluated by differential scanning calorimetry (DSC), TGA, and dynamic mechanical analysis (DMA). The cured resin p(Dz-f) exhibited a glass transition temperature (Tg ) of 391 °C, a very high char yield of 68.7 %, and outstanding thermal stability; the Tg value obtained was the highest thermal stability value ever reported for polybenzoxazine with a high biobased content. Moreover, Dz-f demonstrated a satisfying processability, which was rare for the high-performance thermosetting resins. This work provided us with a new strategy for the preparation of high biocontent resins with excellent thermal properties. In addition, the combination of biobased feedstocks with a microwave-assisted heating method as well as the potential application of this approach in high-end fields might perpetuate remarkable progress towards the sustainable development of the polymeric industry.

A high-resolution-electron-microscopy study of a ?/??-? directionally solidified eutectic alloy: Part I The as-solidified state

The microstructure of a γ/γ′-α directionally solidified (DS) eutectic alloy with a nominal composition of Ni-30.26Mo-6.08Al-1.43V (wt%) was investigated by means of high-resolution electron microscopy (HREM) and analytical electron microscopy. The α-fibres exhibited a typical morphology with a rectangular cross-section and they displayed the Bain orientation relationship (OR) with the γ′/γ matrix; that is, [001]α∥[001]γ′ and (110)α∥(010)γ′. Misfit dislocations and lattice strain fields existed at the α/γ′ interface for different habit planes; that is, (110)α∥(010)γ′ and (100)α∥(110)γ′ were analysed. EDAX (Energy dispersive X-ray) analysis showed that the composition of the γ-phase was approximately Ni4(Mo, Al, V); it contained 90° rotational domains of Ni3(Mo, Al, V) with a DO22 structure and Ni2(Mo, Al, V) with a Pt2Mo structure.

A high-resolution-electron-microscopy study of ?/??-? directionally solidified eutectic alloy: Part II As-ageing treatment

A master alloy with eutectic compositions of Ni-30.26Mo-6.08Al-1.43 V (wt%) has been directionally solidified (DS) into γ/γ′-α alloy. The microstructural as-ageing treatment was studied by means of high resolution electron microscopy (HREM). A majority of α fibres still display the Bain orientation relationship with the γ′/γ matrix. In a few cases, however, the so-called Nishiyama-Wasserman (NW) orientation relationship is found in specimens aged at 850 °C for 2000 h. Different microdomain structures of the γ phase, corresponding to different ageing temperatures, were revealed. Orthorhombic Ni3Mo phase, with a size of tens of nanometres, was found to precipitate inside α fibres after ageing at both 850 and 650 °C. Occasionally, an γ′-Ni3Al phase with lamellar twin structure was also found to coexist with Ni3Mo precipitate inside the α fibres. The orientation relationships between the precipitates and the α fibres were determined. Energy dispersive X-ray analysis (EDX) showed that the precipitation of Ni3Mo and Ni3Al is due to solid solution of Ni and Al in the α fibres.