The polymerization of styrene is monitored by pyrene excimer formation. The ratio of monomer to excimer intensities ( I m/ I e) of pyrene increases as polymerization proceeds. The increase of I m/ I e is ascribed to the increase of microviscosity surrounding the probes forming excimer during polymerization. The linear relationship between the changing rate of I m/ I e and the polymerization rate of styrene is obtained. Therefore, I m/ I e may be used to monitor the progress of the polymerization of styrene.
A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethylpropionate as the initiator.The molecular weight of the resulting polymer increases with increasing monomer conversion.The molecular weight distribution is not narrow(PDI=1.5～1.7),and the value of molecular weight detected is in good accordance with the calculated.The molecular weight distribution is 1.13 with the addition of 10% DMF.
