Tung oil-based unsaturated co-ester macromonomer for thermosetting polymers: Synergetic synthesis and copolymerization with styrene

Authors: LIU, CHENGGUO - Chinese Academy Of Forestry; SHANG, QIANQIAN - Chinese Academy Of Forestry; JIA, PUYOU - Chinese Academy Of Forestry; DAI, YAN - Chinese Academy Of Forestry; ZHOU, YONGHONG - Chinese Academy Of Forestry; Liu, Zengshe - Kevin

Submitted to: ACS Sustainable Chemistry & Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2016
Publication Date: 7/13/2016
Publication URL: http://handle.nal.usda.gov/10113/5309296
Citation: Liu, C., Shang, Q., Jia, P., Dai, Y., Zhou, Y., Liu, Z. 2016. Tung oil-based unsaturated co-ester macromonomer for thermosetting polymers: Synergetic synthesis and copolymerization with styrene. ACS Sustainable Chemistry & Engineering. 4(6):3437-3449.

Interpretive Summary: In this research, we developed a macromonomer containing two functional groups, maleates and acrylates, from tung oil (TO). The resulting bio-plastics from this macromonomer showed excellent mechanical properties. They will be promising eco-friendly rigid biomaterials.

Technical 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 a 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, consequently resulting in rigid bioplastics with high cross-link densities (Ve) and excellent mechanical properties. For instance, the bioplastic prepared under the optimal synthesis conditions demonstrated a Ve of 4.03 X 10 x 3 mol/m3, storage modulus at 25°C of 2.40 GPa, and 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. At last, 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 cross-link 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 compounds.