Effect of the Temperature of Polymerization on the Structure of Butadiene-Styrene Copolymers

Abstract

Abstract The addition of monomer molecules to the growing polymer chain during the polymerization of dienes may take place in several ways. In the polymerization of butadiene, the addition takes place in the 1,2- and 1,4-positions. In the latter case polymer chains are obtained with structural variations, e.g., the position of CH2 groups at the double bonds is cis or trans. The resulting polymer chains vary in configuration. It is of interest to determine how the configuration is affected by different conditions of polymerization. Several papers related to the subject are to be found in the literature. In this work, we studied with an infrared spectrometer the compositions of butadiene-styrene copolymers prepared at different temperatures. Also determined was the content of the various configurations of butadiene links in the polymer chains. The samples were prepared by polymerizing emulsions by the dilatometric method in the absence of oxygen. A satisfactory emulsion was obtained with a magnetic stirrer inserted into the dilatometer (Figure 1 ). The rotation of the stirrer (activated by a magnet attached to the axis of a motor under the thermostat) sucked the upper part of the liquid through the upper opening (1) and expelled it through the side opening (2); this assured emulsification.