ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Crystallization of amorphous poly(phenylene sulfide) was carried out upon annealing in the presence of sorbed CO2 and N2O at pressures of 50 bar. Thermal crystallization at the same pressure allows the comparison of crystallization rates. From the results of IR-spectroscopy, wide angle X-ray diffraction, differential scanning calorimetry and density measurements, it is seen that in the presence of sorbed gas molecules crystallization occurs even at temperatures below the glass transition measured at atmospheric conditions. At a given temperature, gas sorption yields accelerated crystallization. The results, show the considerable plasticizing influence of sorbed gas molecules. From the crystallization rate at sorbed gas conditions the plasticizing ability of the gas may be estimated. That of N2O exceeds that of CO2 by a factor of three. Assuming a simple two-phase model for the crystalline polymer the comparison of heat of melting and density values for t → ∞ allows the conclusion that parts of the noncrystalline volume fraction become less dense by annealing in the presence of sorbed gas molecules. An increased free volume fraction which may be formed in the non-crystalline regions is discussed. It is possible that the remaining lower density results from a hindered relaxation of chain molecules from the dilated state they take due to gas sorption. In this context the influence of decreased mobility of non-crystalline chains is discussed in terms of the “rigid amorphous phase” concept.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1993.021940130
