Infrared Studies of 1,2- and Trans 1,4-Structure of Polybutadiene and Butadiene-Styrene Copolymers Polymerized at Various Temperatures

Abstract

Infrared methods have been used in determining 1,2- and trans-1,4-addition in polybutadiene polymerized in the temperature range −19° to 97° and butadiene-styrene copolymers prepared at −18°, 5° and 50°. trans-1,4-Addition increases and 1,2-addition decreases with decreasing temperature of polymerization. At −19°, substantially all of the 1,4-addition product is present in the trans-1,4-form. Approximately 20 per cent 1,2-addition occurs at this temperature and is concluded to account for the major part of the non-crystallizable portion of polymers made at low temperatures. The influence of styrene on 1,2- and trans-1,4-addition in butadiene-styrene copolymers is also discussed. Free energy, heat and entropy of activation are calculated for 1,4- vs. 1,2-addition and trans-1,4- vs. cis-1,4-addition in the polymerization process.

Midblock-sulfonated triblock ionomers derived from a long-chain poly[styrene-b-butadiene-b-styrene] triblock copolymer

“…36,37 The peak at 960 cm À1 , in particular, can correspond to either the trans-1,4 or cis-1,4 isomer since they are difficult to distinguish. 31 Vibrations from out-ofplane ]CH wagging (due to 1,2 addition during polymerization 38 ), C]C stretching and ]CH stretching in B are responsible for the peaks positioned at 913, 1641 and 3003 cm À1 , respectively. Lastly, a doublet located at 2920 and 2832 cm À1 is a result of CH 2 antisymmetric and symmetric stretching in the B repeat units.…”

Miniemulsion and conventional emulsion copolymerization of styrene and butadiene: Effect of process on gel content

“…The microstructure of copolymers can be affected by factors such as the polymerization system, reaction conditions, and monomer characteristics (solubility, reactivity ratios, monomer/water and comonomer ratio). The microstructure of poly(styrene‐ co ‐butadiene) (SBR) copolymers has been studied using IR,1, 2 NMR,3 and other techniques 4. It was found that, for the conventional emulsion polymerization of SBR, the initiator, surfactant, and chain transfer agent have little or no effect on the microstructure of the resulting emulsion polymers.…”