Poly(styrene)-supported N-heterocyclic carbene coordinated iron chloride as a catalyst for delayed polyurethane polymerization. Issue 65 (7th November 2018)

• Record Type: Journal Article
• Authors: Noh, Hyeon-Jun; Sadhasivam, T.; Jung, Do-Sung; Lee, Keundeuk; Han, Mingu; Kim, Ju-Young; Jung, Ho-Young
• Is Part Of: RSC advances. Volume 8:Issue 65(2018)
• Page Start: 37339
• Page End: 37347
• Publication Date: 2018-11-07
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra07677d
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The Im–FeCl3 catalyst supported by CMPS can control the reaction rate (delaying the curing process) in PUR polymerization. Abstract : An advanced organometallic catalyst based on N-heterocyclic carbene (NHC) coordinated FeCl3 has been synthesized and used to control the reaction rate in polyurethane (PUR) polymerization. The imidazolium (Im)-based NHC was functionalized on the surface of the supporting material of bead-type chloromethyl polystyrene (PS) resin. The PS-Im–FeCl3 catalyst was synthesized through the coordination reaction between Im and FeCl3 . The successful formation, functional groups, structure, and geometry of the PS-Im–FeCl3 catalysts were confirmed by Fourier transform infrared and X-ray photoelectron spectroscopy techniques. A thin layer of Im was observed to be coated uniformly on the PS bead surface and FeCl3 nanoparticles were observed to cover the coating layer homogeneously, as determined by field-emission scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy measurements. The PUR polymerization reaction was investigated through viscosity measurements and non-isothermal activation energy calculations by differential scanning calorimetry analysis. Based on the viscosity measurements, delayed PUR polymerization was achieved using the PS-Im–FeCl3 catalyst system. The highest viscosity (6000 cP) was achieved without any catalyst, with triphenylene bismuth, and with the PS-Im–FeCl3 catalyst after 23, 5, and 25 h of reaction time, respectively. Furthermore, the calculated activation energies ( E a ) were 27.92 and 36.35 kJ mol −1 for the no-catalyst and the PS-Im–FeCl3 systems, respectively. Thus, the viscosity measurements and DSC analyses confirm that the PS-Im–FeCl3 catalyst considerably increases the PUR reaction time. The Im–FeCl3 catalyst supported by CMPS can control the reaction rate in PUR synthesis because of its high activity. Thus, the PS-Im–FeCl3 catalyst can be used as a curing retardant in the PUR industry.