| Abstract: | The specific heat of polystyrenes of different origin and molecular weight, of α-substituted and ortho-substituted polystyrenes, and of polystyrenes crosslinked with different amounts of divinylbenzene have been measured between 1.6 and 4°K. The specific heat of all samples shows a temperature dependence that can not be explained by assuming a Debye frequency spectrum for the vibrational modes in these polymers. Good agreement is obtained by fitting the data to a superposition of a Debye T3 term and an Einstein specific heat with a characteristic temperature of 15–18°K. This localized frequency mode may have its origin in the one-dimensional nature of the polymer chain. A simple calculation of the length of a polystyrene chain necessary to obtain these characteristic temperatures shows reasonable agreement with the number of Einstein oscillators observed in the samples. |
