THERMAL-PROPERTIES OF NYLONS RELATED TO POLYGLYCINE

Aliphatic polyamides (homopolyamides 1.n and n.3 and copolyamides 2/n) were characterized in terms of their thermal properties. These series of isomeric polymers have single isolated methylene groups between th e amide groups and crystallize in different forms intermediate between pseudohexagonal- and polyglycine II-like. Melting and glass transitio n temperatures are reported and compared with literature data. Thermog ravimetry shows that an isolated methylene group imparts thermal insta bility to the nylons, depending on the detailed chemical structure. Th e copolyamides have sharp melting peaks and high crystallinity, when c rystallized from solution, but crystallization from the melt is much s lower. The heat-flow trends are discussed in relation to estimated hea t capacities.