A hyperbranched polymer from tung oil for the modification of epoxy thermoset with simultaneous improvement in toughness and strength

Authors: XIAO, LAIHUI - Chinese Academy Of Forestry; Liu, Zengshe - Kevin; LI, NAN - Nanjing Tech University; LI, SHUAI - Chinese Academy Of Forestry; FU, PAN - Chinese Academy Of Forestry; WANG, YIGANG - Chinese Academy Of Forestry; HUANG, JINRUI - Chinese Academy Of Forestry; CHEN, JIE - Chinese Academy Of Forestry; NIE, XAIOAN - Chinese Academy Of Forestry

Submitted to: New Journal of Chemistry (RSC)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2020
Publication Date: 9/26/2020
Citation: Xiao, L., Liu, Z., Li, N., Li, S., Fu, P., Wang, Y., Huang, J., Chen, J., Nie, X. 2020. A hyperbranched polymer from tung oil for the modification of epoxy thermoset with simultaneous improvement in toughness and strength. New Journal of Chemistry (RSC). 44:16856-16863. https://doi.org/10.1039/C9NJ06373K.
DOI: https://doi.org/10.1039/C9NJ06373K

Interpretive Summary: In this research, we discovered that tung oil based polymers are effective at strengthening epoxy resin. Epoxy resins are widely used in the expoxy resin industry. However, the high cross-linking structure of epoxy resin contributes to the poor fracture strength of the epoxy resin. Our results indicated that the new tung oil based polymers strengthened the epoxy resin. The mechanical properties of the epoxy/polyamine curing system were greatly improved. It will benefit the epoxy resin industry.

Technical Abstract: In order to increase the toughness of epoxy resin and make full use of biological resources, a tung oil-based hyperbranched polymer (TOHBP) was synthesized. The structure of the TOHBP was determined by FTIR, NMR and gel permeation chromatography (GPC). After TOHBP was incorporated into an epoxy/polyetherimide curing system, different analytical studies were carried out to characterize samples of each formation. The results show simultaneous improvement in the impact strength (62.79 KJ•m-2), tensile strength (73.01 MPa), modulus (3116 MPa) and glass transition temperature (Tg) (86.62 °C) compared with neat epoxy resin (20.07 KJ•m-2, 67.97 MPa, 2610 MPa and 81.48 °C, respectively). In addition, the significant improvement in impact strength and the simultaneous reinforcement of other properties suggest that TOHBP provides a better toughening and strengthening ability than many other reported oil-based hyperbranched polymers (HBPs) and petroleum-based polymers. The results indicate that this renewable material is a promising modifier, and may provide an alternative to replace petroleum-based materials that increase the toughness of epoxy resins.