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Aliphatic urethanes. Effect of chain length on some physical properties
Author(s) -
Shulman Sol,
Formo Marvin W.,
Rheineck Alfred E.
Publication year - 1961
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02633233
Subject(s) - thixotropy , melting point , alkyl , moiety , chemistry , molecule , carbon fibers , solvent , organic chemistry , homologous series , polymer chemistry , crystallography , materials science , composite material , composite number
During a study of the thixotropic behavior of certain fatty materials a series of alkyl esters of substituted carbamic acids was prepared, and some of the physical properties were examined. Highly purified fatty aleohols and fatty isocyanates were reacted to give urethanes with from 8 to 22 carbon atoms in both the O‐alkyl and N‐alkyl groups. The melting points of the urethanes were dependent not only on the number of carbon atoms in the molecule but also on the symmetry of the moiety. In an homologous series the melting point increases with the number of carbon atoms. When symmetry is reached, there is a sharp increase in the melting point. After this the increase is less pronounced. The urethanes give thixotropic gels with ethyl alcohol, soybean oil, solvent‐thinned resins, and other similar materials at concentrations as low as 0.5%. In general, better‐defined crystal structure and poorer thixotropic properties were observed with an increase in symmetry.