Yanhua Jiang

Bio-based epoxy resin from itaconic acid and its thermosets cured with anhydride and comonomers

A novel itaconic acid (IA) based epoxy resin with curable double bonds (EIA) was synthesized by the esterification reaction between IA and epichlorohydrin (ECH). Its chemical structure was confirmed in detail by FT-IR, 1H-NMR and ESI-ION TRAP MS before being cured by methyl hexahydrophthalic anhydride (MHHPA). In order to manipulate the properties of the cured resin, divinyl benzene (DVB) and acrylated epoxidized soybean oil (AESO) were employed here to act as comonomers. The results demonstrated that EIA showed a higher epoxy value of 0.625 and higher curing reactivity toward MHHPA compared with the commonly used diglycidyl ether of bisphenol A (DGEBA). The glass transition temperature, tensile strength, flexural strength and modulus of the cured EIA without comonomers were 130.4 °C, 87.5 MPa, 152.4 MPa and 3400 MPa, respectively, which were comparable or better than those of DGEBA cured by the same curing agent. After being copolymerized with DVB or AESO, the properties of the cured EIA could be regulated further. The results indicated that EIA has great potential to replace the petroleum-based thermosetting resin, such as DGEBA.

Synthesis and properties of full bio-based thermosetting resins from rosin acid and soybean oil: the role of rosin acid derivatives

Two kinds of rosin acid derivatives were synthesized to serve as the rigid monomers to copolymerize with acrylated epoxidized soybean oil (AESO). Full bio-based thermosetting resins with satisfactory properties were then prepared. For comparison, petroleum-based divinylbenzene (DVB) was also used to copolymerize with the same AESO. The chemical structures of the synthesized rosin derivatives were confirmed by 1H NMR, 13C NMR and FT-IR before polymerization. The mechanical and thermal properties of the resulting thermosets were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Results demonstrated that the glass transition temperatures, tensile strength and modulus of the cured AESO were significantly improved after copolymerization with the rosin derivatives. The rosin acid derivatives showed great potential to replace petroleum-based rigid compounds for preparing soybean oil-based thermosets. The important information about how to design and synthesize more renewable thermosets with satisfactory properties was provided in this study.

Synthesis and properties of a bio-based epoxy resin from 2,5-furandicarboxylic acid (FDCA)

A bio-based epoxy monomer, diglycidyl ester of 2,5-furandicarboxylic acid (DGF) was synthesized for the first time from the renewable 2,5-furandicarboxylic acid (FDCA). For comparison study, its petroleum-based counterpart, diglycidyl ester of terephthalic acid (DGT) was also prepared. Their chemical structures were confirmed in detail by 1H NMR, 13C NMR and FT-IR before they were cured by methylhexahydrophthalic anhydride (MHHPA) and poly(propylene glycol)bis(2-aminopropyl ether) (D230), respectively. The curing behaviors were investigated using differential scanning calorimetry (DSC). The thermal mechanical properties and thermal stabilities of the cured resins were evaluated using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Results showed that DGF displayed higher curing activity, elevated glass transition temperature and similar mechanical properties compared with those of the cured DGT. This study indicated that FDCA had a huge potential to replace the petroleum-based terephthalic acid in the synthesis of epoxy resins with satisfactory performance.

Highly recoverable rosin-based shape memory polyurethanes

Improving the phase separation and stability of the hard segment domains at the same time is the novel method reported here to improve the recovery of thermoplastic shape memory polyurethanes (SMPUs) at high strain (>1000%). The shape recovery of the corresponding SMPUs with a more than 1000% strain can reach about 96% at room temperature in 3 min, the recoverable strain (emax − epermanent) is more than 960%, which is nearly 2.5 times that of the best value (400%) previously reported.

Bio-based tetrafunctional crosslink agent from gallic acid and its enhanced soybean oil-based UV-cured coatings with high performance

The utilization of soybean oil-based UV coatings depends on the introduction of petroleum-based comonomers or crosslink agents. Thus, in this paper, a bio-based crosslink agent (GACA) for UV curable coatings was synthesized from gallic acid and its chemical structure was confirmed by FT IR, 1H NMR and 13C NMR. Crosslinked networks with high biobased content of more than 88% were obtained after co-photopolymerization between acrylated epoxidized soybean oil (AESO) and GACA. The thermal, mechanical and coating properties of these GACA crosslinked AESO networks were investigated and a commonly used crosslink agent triallyl isocyanurate (TAIC) was used as the control. GACA exhibited more functional groups and better copolymerization with AESO than TAIC, resulting in the higher gel content, crosslink density, tensile strength and modulus as well as much better coating properties (reflected by the higher pencil hardness, better wear resistance and adhesion) of GACA crosslinked AESO networks than TAIC crosslinked AESO networks. These results indicated that GACA exhibited great potential to replace petroleum-based crosslink agents such as TAIC, and high-performance soybean oil-based UV-cured coatings with high biobased content could be achieved after introducing GACA.

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.

Copolyesters Based on 2,5-Furandicarboxylic Acid (FDCA): Effect of 2,2,4,4-Tetramethyl-1,3-Cyclobutanediol Units on Their Properties

Bio-based polyesters derived from 2,5-furandicarboxylic acid (FDCA), including poly (ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), and poly(butylene 2,5-furandicarboxylate) (PBF) have been synthesized and modified with 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Copolyesters with increased glass transition temperature, good barrier and better mechanical properties, as well as higher transparency were reported in this work. The chemical structures, composition, and sequence distribution of the copolyesters were determined by 1H NMR and 13C NMR. The degree of random (R) was close to 1 for all the copolyesters, indicating their random chemical structures. With the introduction of 10% CBDO units, the semi-crystalline PEF and PPF were changed into completely amorphous polyesters and the higher transparency was easily achieved. The glass transition temperature was increased from 87 °C for PEF to 91.1 °C for PETF-18, from 55.5 °C for PPF to 63.5 °C for PPTF-18, and from 39.0 °C for PBF to 43.5 °C for PBTF-18. The barrier properties investigation demonstrated that although the O2 and CO2 barrier of PEF/PPF/PBF were decreased by the addition of CBDO units, the modified copolyesters still showed good barrier properties.

Bio-based shape memory epoxy resin synthesized from rosin acid

A bio-based shape memory epoxy resin (DGEAPA) was synthesized from rosin to achieve the sustainability of shape memory epoxy resin, and its chemical structure was determined by FTIR and 1H NMR. For comparison, a petroleum-based epoxy, diglycidyl ester of terephthalic acid (DGT) having one benzene ring, was also synthesized. The properties, including thermal and mechanical properties, as well as shape memory properties of the epoxy resins cured with poly(propylene glycol)-bis (2-aminopropyl ether) (D230), were studied by differential scanning calorimeter, dynamic mechanical analysis, thermogravimetric analysis, tensile test, and U-type shape memory test. The effect of the stoichiometric ratio nDGEAPA/nDGT on the properties was studied as well. The thermal and mechanical properties, including thermal stability, glass transition temperature, tensile strength, and modulus of the cured epoxy systems, were found to be increased with DGEAPA incremental content, and the cured neat rosin-based epoxy system exhibited the highest properties. Both the cured rosin-based epoxy and the cured DGEAPA showed significant shape memory performance. Meanwhile, the rosin ring structure made the cured rosin-based epoxy systems display excellent shape recovery fixity, while small lower shape recovery and shape recovery rate relative to the cured neat DGT system. Therefore, the rosin-based epoxy resin has a great potential in the shape memory material applications.