GPC Data Interpretation in Mechanochemical Polymer Degradation

Abstract Molecular weight distribution obtained by gel permeation chromatography (GPC) conceals a wealth of mechanistic information which can be disclosed only after adequate data treatment. This paper discusses how GPC chromatograms may be used for the elucidation of polymer degradation kinetics. The case of ultrasonic degradation of dilute polystyrene solutions was investigated in detail. The extent of bond scission was determined as a function of sonication time and initial polymer molecular weight. Different bond scission mechanisms were evaluated by comparing calculated molecular weight distributions with experimental data. Best agreement was obtained when multiple fragmentation was included in the degradation scheme, a result experimentally supported by spectroscopic chain ends titration. The results are rationalized by establishing a parallelism between transient elongational flow and ultrasonic degradation.

[1]  A. Kotliar,et al.  Evaluation of molecular size distributions and molecular weight averages resulting from random crosslinking and chain-scission processes , 1961 .

[2]  A. Emsley,et al.  Computer modelling of the degradation of linear polymers , 1995 .

[3]  Willi Jäger,et al.  Modelling of Chemical Reaction Systems , 1981 .

[4]  K. Ebert,et al.  Ultrasonic degradation of polymers in solution , 1977 .

[5]  Bradley P. Barber,et al.  Toward a hydrodynamic theory of sonoluminescence , 1993 .

[6]  M. Luda,et al.  Monte Carlo simulations of polymer degradations. 1. Degradations without volatilization , 1990 .

[7]  H. Kausch,et al.  Absolute peak broadening calibration in size-exclusion chromatography using a polymer-bound chromophore , 1988 .

[8]  Klaus H. Ebert,et al.  Modelling of Polymer Degradation Reactions , 1981 .

[9]  A. Hamielec,et al.  Chemical modification of polyolefins by free radical mechanisms: a modelling and experimental study of simultaneous random scission, branching and crosslinking , 1994 .

[10]  A. Hamielec,et al.  Solution of Tung's axial dispersion equation by numerical techniques , 1971 .

[11]  H. Kausch,et al.  Mechanochemical degradation in transient elongational flow , 1992 .

[12]  Timothy J. Mason,et al.  Sonochemistry : theory, applications and uses of ultrasound in chemistry , 1988 .

[13]  O. Saito.  On the Effect of High Energy Radiation to Polymers I. Cross-linking and Degradation , 1958 .

[14]  D. Shortt.  Differential Molecular Weight Distributions in High Performance Size Exclusion Chromatography , 1993 .

[15]  A. Shyichuk,et al.  A determination of rates ratio of simultaneous crosslinking and scission from MWD shape , 1995 .

[16]  K. Ebert,et al.  Ultrasonic degradation of polymers in mixed solvents , 1978 .

[17]  W. Kuhn,et al.  Über die Kinetik des Abbaues hochmolekularer Ketten , 1930 .

[18]  B. Wolf,et al.  Degradation of chain molecules. 1. Exact solution of the kinetic equations , 1981 .

[19]  Hidetaka Tobita,et al.  Simulation model for the modification of polymers via crosslinking and degradation , 1995 .

[20]  H. Kausch,et al.  Some emerging techniques in polymer mwd characterization , 1996 .

[21]  J. Bendler,et al.  A spin-lattice relaxation study of dissolved cyclohexyl polycarbonate , 1996 .

[22]  Henning-H. Kausch,et al.  Kinetics of polymer degradation in transient elongational flow , 1989 .

[23]  S. Girois,et al.  Polym. Degrad. Stab. , 1996 .

[24]  H. Kausch,et al.  Chain scission in transient extensional flow kinetics and molecular weight dependence , 1988 .

[25]  E. Montroll,et al.  Theory of Depolymerization of Long Chain Molecules , 1940 .

[26]  H. Kausch,et al.  Degradation on freezing dilute polystyrene solutions in p-xylene , 1994 .

[27]  Tuan Q. Nguyen,et al.  Kinetics of mechanochemical degradation by gel permeation chromatography , 1994 .

[28]  R. Gilbert,et al.  Molecular Weight Distributions in Free-Radical Polymerizations. 1. Model Development and Implications for Data Interpretation , 1995 .