ISSN:
0449-2951
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A scattered-light photometer particularly adapted to high temperature work has been designed and constructed. Among the desirable features are constant monitoring of the primary beam, placement of photodetectors outside the heated zone, output proportional to ratio of outputs of matched detectors, thus to Rayleigh's ratio, insensitivity of output readings to light absorption by the solution, temperature control from room temperature to 150°C. The geometrical factors affecting output readings have been analyzed and the instrument calibrated using several standards. Techniques developed for hot solution clarification and the measurement with good precision of weight-average molecular weights of ethylene polymers are described. The results for several typical unbranched Marlex polyethylenes are given covering the range 80,000-170,000. Depending on the polymer, the ratio weight-average to number-average varies from 10 to 16 for whole Polymer. The z-average molecular weights estimated from the mean-square molecular radii are used to estimate Mz/Mw ratios.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1964.100020113
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