ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
A series of nine poly(N-n-alkylmaleimide)s (PMIs) with the n-alkyl side chain ranging in length from ethyl to octadecyl and including only the even members of the series was studied by differential scanning calorimetry (DSC) from 100 K to above the glass transition temperature. The nine members of the PMI series generally were found to exhibit a glass transition temperature (Tg), a sub-glass transition temperature (sub-Tg = Tγ), and, but only the four higher homologs a melting point (Tm) with the respective melting enthalpy (ΔHf). The glass transition of the amorphous members is directly related to the number of methylene groups (including terminal methyl) of the n-alkyl side chain of the repeating unit. The values of Tg estimated according to a semi-empirical equation are in good agreement with the experimental data. The melting points of the members of the series presenting crystallinity in the n-alkyl side chain were analyzed. A good fit of a Garner plot by a least-mean-squares procedure is obtained with T0m = 408,0K, a = -6,26 and b = -2,03. The contribution to the heat of melting per methylene unit clearly demonstrates that the hexagonal paraffin crystal structure is present in the crystalline members, in agreement with X-ray data. The data when analyzed by Jordan′s procedure show that only part of the n-alkyl side chain is forming a crystal lattice.
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1983.021841222
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