ISSN:
0449-296X
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Vapor-phase osmometric molecular weight measurements on beryllium di-n-butyl-phosphinate are in general agreement with the results obtained in chloroform by Ripamonti and co-workers. The degree of polymer association in anhydrous chloroform is approximately twice that obtained in reagent-grade chloroform, and the values obtained in both types of chloroform are higher than those obtained by Ripamonti. Membrane osmometric molecular weight measurements on beryllium 4-biphenyl (phenyl)-phosphinate in chloroform indicate a reversible degradation exists between a number-average molecular weight of 170 000 and 30 000, with the value dependent upon the polymer concentration. Treatment of chloroform solutions of this polymer with ammonia prevents reassembly of the polymer from 30 000 to higher values. To explain this and other solution properties of this polymer, a structure is proposed which involves endgroup hydrogen bonding of phosphinate-bonded aggregates containing approximately 50 monomer units (Mn = 30 000). Under certain conditions, the hydrogen-bonded aggregates may contain up to 300 monomer units, but in polar solvents such as water or chloroform they are rapidly degraded.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1970.150080603
