Thermodynamics of cationic polymerization. 3. Examples

Abstract

Thermodynamic relations of cationic polymerization are reported. According to previously derived estimations, presumptions concerning the ratio rl : r2 for different copolymerization systems are made. Most of them are confirmed by the experiment. Three reasons for the preferred polymerization of isobutene from a C4-fraction are discussed. Among them is a "repairing mechanism", which leads to a consumption of the other components in the mixture of not more than 10%. An explanation is given for the increase of the double bond content in the polymer during the end of the copolymerization reaction. Zur Thermodynamik der kationischen Polymerisation. 3. BeispieleThermodynamische Zusammenhange der kationischen Copolymerisation werden betrachtet. Entsprechend friiher abgeleiteten thermodynamischen Abschatzungen werden Voraussagen zum Verhaltnis rI : r2 fur verschiedene Copolymerisationssysteme getroffen, wobei in der Mehrzahl der FIlle die Voraussage experimentell bestatigt wurde. Drei Griinde fir die bevorzugte Polymerisation des Isobutens aus einer Ca-Fraktion werden angegeben, u. a. ein ,,Repariermechanismus", der den Verbrauch der anderen Monomere nicht iiber 10% steigen IaBt. Es wird eine Erklarung fur das Ansteigen des Doppelbindungsgehaltes der Polymere zum Ende der Reaktion gegeben.nism. This was the continuation of the method used by PLESCH [3] and SAWADA [4] in the field Of cationic polymerization. A thermochemical analysis of the initiation process from the point of view of the initiating agent Was given by PLSCH [5]. In the present paper some examples for the use of thermochemical data are given to discuss the results in our own work.