Synthesis of vegetable oil based hyperbranched polyol
A novel bio-based hyperbranched polyol (HBP) with high functionality was prepared from grapeseed oil (GSO) through the following sequential steps: i) epoxidation, ii) propargylation and iii) thiol-yne click reaction. Structural analysis confirmed that the GSO-based HBP was synthesised successfully; and the hydroxyl value of the synthesised HBP was 612 mg KOH/g, which is close to that of commercialised HBP. Furthermore, the prepared HBP was employed as a crosslinker to fabricate bio polyurethane (PU) films via a two-step prepolymer polymerisation.
Tensile strength and tensile elongation significantly increased
The successful synthesis of hyperbranched PUs was confirmed by Fourier transform infrared analysis. Moreover, according to the results of X-ray diffraction analysis, the crystallinity of the prepared hyperbranched PUs decreased because the crosslinked networks hindered the formation of crystalline structures. Based on the mechanical property analysis, it was confirmed that the tensile strength and elongation of PU using HBP reached 27 MPa and 2315%, respectively. From these results, it can be confirmed that the tensile strength and tensile elongation of the PUs significantly increased upon the introduction of a crosslinker with a hyperbranched structure.
The study has been published in Progress in Organic Coatings, Volume 164, March 2022.