ISSN:
0449-2978
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The determinations of the number-average molecular weight of polyethylene by cryoscopy has been improved, permitting precise measurements with both linear and branched polyethylenes in the molecular weight range 4,000-30,000. Improvements include a cryometer of new design, a lower-melting cryoscopic solvent containing a nucleating agent to control supercooling and rate of crystallization of the solvent, and more precise measurement of freezing point depression. Polyethylene samples are dissolved in hexamethylbenzene admixed with 0.1% of cadmium iodide, and steady-state freezingpoint depressions are measured with a thermistor to a maximum sensitivity of 5 × 10-5°C. Molecular weight measurements are reproducible to within ±10%. The cryoscopic apparatus and procedure are described in detail, and results obtained with samples of linear and branched polyethylene are presented and discussed.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1966.160040504
