Physico-chemical studies of polyamides II : aromatic polyamides having long methylene chain units

Abstract

Two series of polyamides having long methylene chain units have been prepared from p-xylylenediamine and 2, 2'-p-phenylenebisethylamine with α, w-thia-alkanedioic acids of long methylene chain units ; aliphatic diamines of long methylene chain units with terephthalic, benzene-1, 4-diacetic, and benzene-1, 4-dipropionic acids. The effects of the length of methylene chain units on the melting points, the glass transition temperatures and the densities of these polyamides were investigated. The aromatic polyamides, in which even methylene chains are present between a phenylene and an amide group generally have higher melting points and densities, than the corresponding ones with odd methylene chains. The melting points of polyamides having thioether linkages are lower than those of corresponding long methylene polyamides.