Chuanzhi Zhang

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.

Preparation and characterization of poly(lactic acid)/starch composites toughened with epoxidized soybean oil.

Blends of entirely bio-sourced polymers, namely polylactide (PLA) and starch, have been melt-compounded by lab-scale co-extruder with epoxidized soybean oil (ESO) as a reactive compatibilizer. The starch granules were grafted with the maleic anhydride (MA) to enhance its reactivity with ESO. The ready reactions between the epoxy groups on ESO, the MA groups on MA-grafted starch (MGST) and the end carboxylic acid groups of PLA brought blending components together and formed a compatible compound. An elongation at break (EB) of 140% was obtained in the blend of PLA/MGST/ESO (80/10/10), increased from 5% of a pure PLA. The grafting content of the MA on the starch granules primarily determined the compatibility and properties of the ternary blends, which was also affected by the relative amount of MGST and ESO.

Effect of castor oil enrichment layer produced by reaction on the properties of PLA/HDI-g-starch blends

Blends of entirely bio-sourced polymers, namely polylactide (PLA) and starch, have been melt-compounded by lab-scale co-extruder with castor oil (CO) as a plasticizer. The enrichment of castor oil on starch had great effect on the properties of the blends. If the castor oil was mainly dispersed in PLA matrix, the properties of the blends were poor, but when the hexamethylenediisocyanate (HDI) was grafted on starch granules the ready reactions between the hydroxyl on CO and the isocyante on the HDI-grafted starch (HGSTs) brought CO molecules enriched on starch particles. DSC analysis shows that the CO layer on starch has a positive effect on the crystallization of PLA in the ternary blend. The accumulation of CO on starch greatly improves the toughness and impact strength of PLA/starch blends. The grafting content of HDI on the starch granules primarily determined the compatibility and properties of the resulted blends.

Synthesis, Characterization of a Rosin-based Epoxy Monomer and its Comparison with a Petroleum-based Counterpart

A bio-based epoxy derived from dehydroabietylamine was synthesized. In comparison, its petrochemical counterpart based on benzylamine was also prepared. Their chemical structures were confirmed in detail by Fourier Transform Infrared Spectra (FT-IR) and Nuclear Magnetic Resonance (1H-NMR and HSQC). The curing reactions of these synthesized epoxies with hexahydrophthalic anhydride were studied by Differential Scanning Calorimeter (DSC). The mechanical properties and thermal stability of the cured epoxies were investigated by Universal Mechanical Testing Machine, Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analyzer (TGA), respectively. The results indicated that the bulky fused diterpene structure in dehydroabietylamine led to a weaker molecular motion ability and a lower cross-link density, so that the cured epoxy derived from dehydroabietylamine processed a higher glass transition temperature (167°C), but lower mechanical properties than those of the benzylamine-based one.