ISSN:
0449-2951
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A study has been carried out on the molecular weight distributions of polystyrene initiated by sodium naphthalene in tetrahydrofuran solution. Stringent high-vacuum techniques were used in order to minimize initiator destruction or chain termination. Molecular weights were measured by osmotic pressure, dilute solution viscosity, light scattering and sedimentation equilibrium. In general, the molecular weight distributions found were quite narrow, as predicted, and corresponded to a stoichiometry of one polymer chain for two initiator molecules. However, the breadth of the distribution was very sensitive to experimental conditions, the M̄w/M̄n values found ranging from 1.1 to 1.5. At the higher molecular weights, there was some indication of a chain transfer reaction, leading to a lower molecular weight than expected, as well as a broadening of the distribution. This transfer reaction did not appear to be due to any transfer step between the short-lived radical-anions and the solvent.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1963.100010139
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