ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Values of the mean-square dipole moment 〈μ2〉 of poly(diethylene glycol isophthalate) were determined as a function of temperature by means of dielectric experiments carried out on solutions of the polymer in benzene. The value of the dipole moment ratio 〈μ2〉/(nm2), where nm2 is the mean-square dipole moment of the chains in the idealization that all of the skeletal bonds are freely jointed, is 0,697 at 30°C. Trifunctional model networks were prepared by endlinking hydroxyl-terminated chains with an aromatic triisocyanate. From thermoleastic experiments performed on the networks over the temperature range 20-80°C, it was found that the value of the temperature coefficient of the unperturbed dimensions 103 d In 〈r2〉0/dT amounts to 1,05 ± 0,17 K-1. The dipole moments and the temperature coefficients of both the dipole moments and the unperturbed dimensions were critically interpreted in terms of the Ratational Isomeric State (RIS) model. Stress-strain experiments were also performed at 70°C on swollen and unswollen networks. The analysis of the isotherms suggests that the chemical crosslinks are not sufficient to account for the high modulus exhibited by the networks.
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1984.021850916
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