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Structure–property relationships in polyamides containing cyclohexylene or phenylene structures

1974; Wiley; Volume: 12; Issue: 9 Linguagem: Inglês

10.1002/pol.1974.170120914

1542-9369

James S. Ridgway,

Synthesis and properties of polymers

Abstract Polyamides were prepared from linear, aliphatic dicarboxylic acids of six to twelve carbon atoms with 1,4‐cyclohexanebis(methylamine), 1,4‐cyclohexanebis (ethylamine), p ‐xylylenediamine, and p ‐phenylenebis(ethylamine). Melting points, glass transition temperatures, densities, and moisture regains were compared for the polymers to determine the relative effect of the cyclohexylene and phenylene linkages. While polyamides containing the trans ‐cyclohexylene group possessed higher glass transition temperatures than their aromatic counterparts, melting behavior was not as consistent. The odd‐even rule, which states that polyamides with an even number of methylene linkages between the ring and the functional group melt higher than those with an odd number of such linkages, was violated in the cycloaliphatic systems. The T g of ring‐containing polyamide fibers was not dependent solely upon ring concentration, but was influenced by the molecular fit of the ringed intermediate in the polymer chains. Molecular fit appears to affect the T g and melting point of alicyclic polyamides to a greater extent than the aromatic analogs. Differences in T g , both within and among the polymer series, was not explained by either density or the degree of crystallinity.