S P O P M BThe thermal stabilities of polybutadienyllithium, polyisoprenyllithium, and polystyryllithium solutions have been determined in hydrocarbon solvents. Kinetic analysis indicated that a complex mechanism was involved in the thermolysis of polybutadienyllithium. The thermal stability was observed to increase with increasing lithium concentration, suggesting the presence of competitive reactions in addition to the expected elimination of lithium hydride. The thermal stability of the three systems studied was consistent with their reported degrees of association: dimeric polystyryllithium was less stable than tetrameric polyisoprenyllithium or hexameric polybutadienyllithium.

Changes in the properties of linseed oil during heat bodying have been studied in an attempt to correlate such changes with the chemical reactions which are believed to occur.

A method for simultaneously determining the molecular weight averages, molecular weight distribution, hydroxyl equivalent weight, functionality averages, and functionality distribution of hydroxyl‐terminated polybutadienes using GPC has been developed. The method is based on the preparation of a UV absorbing derivative of the hydroxyl group and GPC analysis using dual differential refractive index and UV detectors. In order to determine the hydroxyl equivalent weight, quantitative derivatization of the hydroxyl group is required. If the equivalent weight can be determined by an independent method, the derivatization reaction can be less than quantitative if sufficient UV absorptivity can be obtained. The procedure used for calibrating the GPC columns and UV detector are presented. Equations for calculating number‐ and weight‐average functionalities from GPC data were also developed. The number‐average functionality is independent of the functionality distribution, but the weight‐average functionality is dependent upon the distribution of functionality. The ratio of the weight‐average to number‐average functionality is indicative of how the functionality is skewed as a function of molecular weight.

SynopsisThe functionality averages, functionality distribution, hydroxyl equivalent weight, molecular weight averages, and molecular weight distribution of three commercial hydroxyl terminated polybutadienes have been determined using a dual-detector GPC method used to analyze the polymers before and after derivatization with phenyl isocyanate. The values of these parameters are compared with existing literature data. The determined number-average functionalities were in reasonable agreement with previously published values. However, the distribution of functionality as a function of molecular weight differs from distribution data obtained by column fractionation techniques. Our distribution data appears to be generally consistent with the distribution expected from the polymerization mechanisms. The differences in the variation of hydroxyl content with molecular weight obtained from the dual-detector GPC method and the column fractionation procedures should be resolved since a combination of these procedures could provide additional information regarding the actual amounts of mono-, di-, and polyfunctional polymer and their molecular weight distributions. The dual-detector GPC method should be applicable for the determination of the distribution of a variety of functional groups provided a selective derivatization reaction is available or a second detector which can directly and accurately determine the concentration of the functional group is available.

changes with time in the numerical values of the three parameters are shown in Fig. 12.These a.c. measurements are far from complete, for they must be taken for most of the materials studied' for d.c. leakage before broad conclusions can be drawn. It will be important to establish, the order in which these materials are arranged in terms of either fractional change in capacitance or maximum dissipation factor and to determine the corresponding values of storage coefficient and relaxation frequency in order to set a frequency limit beyond which humidity has no appreciable effect. ACKNOWLEDGMENT