High throughput characterization of biopolyol using DART-MS with ultra-fast polarity switching

The liquefaction of starch in the presence of glycerol with sulfuric acid as a catalyst was conducted. The obtained liquefied starch was added propylene oxides, which could decrease viscosity of the product and increase reactivity with polyisocyanates.
First, starch as the raw material biomass was analyzed by DART-MS. Starch is a polymer consisting of alpha glucose (C6H12O6, MW180). The signal at m/z 342 , m/z 504 in positive ion mode can be assigned to disaccharide ([disaccharide+NH4-H2O]+), trisaccharide ([Trisaccharide +NH4-H2O]+), respectively. The spectrum in negative mode shows characteristic signal interval of 162u. It corresponds to glucose after the loss of H2O([Glucose-H2O]). These signals in negative mode possibly are fragments (oligosaccharides) originating from polysaccharides in starch. These spectra were more dominant in both polarities at temperature setting of 500C than 350C. It was suggested that 500C was the suitable temperature setting to analyze PO-added liquefied biomass (biopolyol).
Next, liquefied biomass, biopolyol, the polyurethane foam derived from the latter and reagents were analyzed. In the case of analyses for biopolyol and the foam, several peaks were widely observed from low molecular weight spectra to high molecular weight spectra. In the spectrum of biopolyol, it was observed characteristic signal interval of 58u in both polarities. The same signal interval was also observed in the spectrum of foam made from biopolyol. But the signal interval of 58u was not found in liquefied starch analysis. Signal interval of 58u probably corresponds to the propylene oxide (C3H6O). It shows that propylene oxides graft copolymerize to liquefied starch. The lower viscosity of biopolyol was, the more 58u interval signals in mass spectra was observed. It suggested that the amount of PO addition related to the viscosities of biopolyols. It could be one of the reasons that the addition of POs makes weaken hydrogen bondings among the liquefied starch molecules.