Dependence of the glass transition temperature of poly[N‐(n‐alkyloxy‐carbonyl‐methyl) Maleimides] and poly[N‐(5‐n‐alkyloxycarbonyl‐n‐pentyl) Maleimides] on n‐alkyl side‐chain length

The glass transition temperature has been determined by a refractometric technique for two homologous series of poly[ N ‐( n ‐alkyloxycarbonyl‐methyl) maleimides] (PEMIS 1) and poly[N‐(5‐n‐alkyloxycarbonyl‐n‐pentyl) maleimides] (PEMIS 5) with the outer part of the n ‐alkyl side‐chain ranging in length from ethyl to decosyl for PEMIS 1 and from ethyl to decyl for PEMIS 5 and including only the even members of the series. The glass transition temperature is directly related to the number of methylene groups in the outer part of the n ‐alkyl side‐chain (including terminal methyl) of the repeating unit. A semiempirical equation is presented that affords estimates of T g that are in good agreement with the experimental data.