FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance (ATR) immersion probe was utilized to study in situ coordination polymerization of butadiene (Bd) in hexane (HEX) with Neodymiumbased catalyst.The relationship of their intensity at signal bands of Bd and its concentration were investigated.The kinetic studies of polymerization of Bd were conducted by in situ ATR\|FTIR.The signal band at 1592 cm-1 was assigned to the stretching vibration of Bd

and the signal bands at 1010 cm-1 and 904 cm-1 were assigned to the deformation vibration of Bd.The Bd/HEX solution exhibited only the above three signal bands of Bd in the FTIR spectrum

and solvent interference was negligible when HEX spectrum was chosen as the background.All the intensity at the signal bands of 1592

1010 and 904 cm-1 were found to be proportional to the Bd concentration in the range of 0.46～3.88 mol#12539;L-1.The stronger signal band at 904 cm-1 was chosen to monitor the Bd concentration during polymerization

and the Bd conversion was calculated on the basis of the linearity dependence of Bd concentration on the corresponding peak intensity at 904 cm-1.The agreement between the FTIR and conventional (gravimetric) kinetic data is excellent in all four sets of experiments.It is evident that signal band at 904 cm-1 can be used for the convenient realtime monitoring of Bd polymerization.The firstorder plots were linear at different polymerizations and thus polymerization rate was first order with respect to monomer concentration.The polymerization rate increased with increasing polymerization temperature

and the apparent propagation activation energy was determined to be 56.5 kJ#12539;moL-1.The GPC traces of polybutadiene products obtained at different polymerization temperatures exhibited relatively narrow unimodal molecular weight distribution

and polydispersity index (Mw/Mn) was around 2.5.The molecular weight of resultant polymers increased linearly with monomer conversion.The polybutadienes with high cis-1

4 configuration ranging from 98.0% to 99.2% and low vinyl configuration of around 0.4% could be prepared with Neodymium-based catalyst

leading to low Tg and some crystal line formation observed in DSC and POM analysis