Synthesis and properties of some new polyimidosulfides with highly mobile backbones

Various alkanedithiols [HSRSH; R = (CH₂)_3–6 or? CH₂CH₂OCH₂CH₂? ] add to the carbon-carbon double bonds of N,N′-bismaleimido-1,8-octane ( 1 ) at room temperature in m-cresol that contains triethylamine as a catalyst to produce the corresponding polyimidosulfides ( 3 ) in yields of 75–86% and with inherent viscosities (ηinh) of 0.30–1.05 dL/g. In general ( 3 ) are amorphous, elastomeric materials that undergo glass transitions (T_g) within the range of 6.5–13°C but product ( 3a ) [R = (CH₂)₆] is a tough, leatherlike polymer that exhibits T_g = 35°C and a melting transition at 77°C. X-ray analysis indicates that ( 3a ) is ca. 37% crystalline. In addition to further details of the synthesis and properties of polyimidosulfides ( 3 ), comparisons are made between crystalline ( 3a ) and a structurally analogous but morphologically dissimilar, elastomeric polyaspartimide synthesized earlier

1 J. E. White, M. D. Scaia, and D. A. Snider, J. Appl. Polym. Sci., in press.

from ( 1 ) and N,N′-dimethyl-1,6-hexanediamine.