Synthesis And Characterization Of Polyether Polyols

Polyether polyol(PPG) is the most important material of soft,rigid,semi-rigid polyurethane foam.It has great application value to determine the molecular weight and its distribution of PPG on the synthesis of PPG and modification of polyurethane materials.Four kinds of PPG samples were synthesized by ethylene glycol,glycerol, trimethylolpropane(TMP) and pentaerythritol.The molecular weights were measured by GPC,and the experiment conditons were established.The relative standard deviation of the results was smaller than 5%when the conditions were as follows:concentrations between 1.0～3.0 mg·mL^-1,column temperature between 30～50℃and the flow rate of mobile phase between 0.7～1.5 mL·min^-1.Compared to the results calculated from hydroxyl value,the relative errors were less than 5%.Propylene oxide as monomer,trimethylamine as catalyst,glycerol,TMP and mixture of glycerol with sucrose(molar ratio 4:1) as initiators,samples of 5 different molecular weights were synthesized.FTIR,¹H-NMR and Electrospray Ionization Mass Spectrometry(ESI-MS) were used to characterize the structure of PPG samples.The hydroxyl values were tested based on GB12008.3-89 and the molecular weights were calculated.GPC was used to determine the molecular weights under the column temperature of 30℃,35℃and 40℃.Method to analyse ESI mass spectrum of PPG samples was established.The mass-to-charge ratio(m/z) data was processed by linear fitting,the molecular weight of monomers and initiators differed from the slope and the intercept of the line respectively.The relative error of the results was less than 0.5%.The theoretical m/z data of PPG ESI spectrums were calculated and listed in datasheets.The molecular weight of PPG samples were obtained from the m/z of ion peaks and the relative abundance of each peak.Ubbelohde viscometer was used to measure the intrinsic viscosity of PPG samples. Together with the molecular weight measured by two methods(calculated from hydroxyl value and measured by GPC),the parameters of Mark-Houwink Equation K andαwere obtained.Experiments showed that relative error of the results between calculated from Mark-Houwink Equation and from experiments were all smaller than 5%.