Chengguo Liu
Chinese Academy of Forestry, China
Title: Novel tung oil-based unsaturated ester macromonomer for thermosetting polymers
Biography
Biography: Chengguo Liu
Abstract
A novel unsaturated co-ester (co-UE) macromonomer containing both maleates and acrylates was synthesized from tung oil (TO) and its chemical structure was characterized by FT-IR, 1H-NMR, 13C-NMR, and gel permeation chromatography (GPC). The monomer was synthesized via new synergetic modification of TO by introducing maleic groups first and acrylic groups subsequently onto TO molecules. The influence of experimental factors on thermo-mechanical properties of the cured bioresins was evaluated to better understand structure-property relationships of the biomaterials and optimize experimental conditions. The obtained TO-based co-UE monomer possessed a highly polymerizable C=C functionality (2.27 per fatty acid), consequently resulting in rigid bioplastics with high crosslink densities (νe) and excellent mechanical properties. For instance, the bioplastic prepared under the optimal synthesis conditions demonstrated a νe of 4.03×103 mol/m3, storage modulus at 25°C of 2.40 GPa, glass transition temperature (Tg) of 127°C as well as tensile strength and modulus at 36.3 MPa and 1.70 GPa, respectively. A new theory for determining optimal comonomer concentration was further developed according to the copolymerization equation. The proposed theory accurately predicted the best styrene dosage for the co-UE monomer. Finally, the hydroxyethyl acrylate (HEA)-modified TO-based resin was compared with the unmodified one in thermo-mechanical properties, thermal stability, microstructural morphologies, and curing behaviors. The new co-UE bioresin showed higher C=C functionality and crosslink density, superior properties including Tg and thermal stability, and similar curing behaviors. The developed eco-friendly rigid biomaterials provide potential application in structural plastics such as sheet molding compound.