Unsaturated canola oil-based polyol as effective nucleating agent for polyurethane hard segments

Abstract

The polyurethane (PU) phase separation could significantly affect its properties. Many factors influence PU phase separation, including soft and hard segments type, their content, and presence of external components such as nanoparticles. The aim of this research was to control the PU phase separation behavior by an internal component which was chemically bonded in PU backbone. For this purpose, a low molecular weight polyester was synthesized and used as a co-soft segment for PU synthesis. The polyester was synthesized by hydroxylation and esterification reaction of unsaturated bonds of raw Canola oil. The PUs were synthesized by two-step polymerization method of poly tetramethyleneglycol (PTMG) and synthesized polyester as soft segments, hexamethylene diisocyanate (HDI), and 1,4 butanediol in 1:3:2 M ratio. In order to study the chemical structure of synthesized materials, specifying the nucleating ability of the synthesized polyol for hard segments, as well as studying its effects on PU properties, different analysis including Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD), Dynamic Mechanical Thermal Analysis (DMTA) and gas permeability were used. Results showed that the presence of the synthesized polyester in the PU structure significantly affects its properties and caused appearance of a new domain for hard segments. These results suggested that polyester polyol can change the PU micro-phase separation by changing hard segments crystalline order.