Caractérisation par spectrométrie de masse MALDI–TOF de poly(isosorbide-éther)s cycliques et linéaires obtenus sous irradiation microondes

Characterisation of cyclic and linear poly(isosorbide-ether)s obtained under microwave irradiation by MALDI–TOF mass spectrometry. We studied the influence of the alkyl chain length and of the leaving group on the fraction of cyclic or linear poly(isosorbide-ether)s. A survey by MALDI–TOF MS showed that cyclic chains (C) are predominant when some short aliphatic chains are used (m = 4 or 6), whereas with longer chains (m = 8, 10 or 12), we noted that cyclic products were in a minority, whatever the leaving group (bromide or mesyl). Important non-thermal microwave effects have been demonstrated, notably a methanol-insoluble fraction of polyether considerably larger than the one obtained by conventional heating. These poly(isosorbide-ether)s have been characterized by RMN, MALDI–TOF, SEC, elementary analysis, and DSC. The survey of the thermal behaviour by DSC showed that the temperatures of fusion increase with the aliphatic chain's length (m = 12; T_f = 37 °C).