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Thermal analysis of poly(phenylene sulfide) polymers. I: Thermal characterization of PPS polymers of different molecular weights
Author(s) -
Menczel Joseph D.,
Collins George L.
Publication year - 1992
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760321713
Subject(s) - materials science , phenylene , polymer , crystallization , glass transition , nucleation , amorphous solid , polymer chemistry , melting point , thermodynamics , chemical engineering , crystallography , composite material , chemistry , physics , engineering
Thermal properties of Fortron® ®Registered trademark of Hoechst Celanese Corporation. poly(phenylene sulfide) (PPS) polymers of different molecular weights were studied by DSC. Crystallization studies revealed that the ability of these polymers to crystallize decreases with increasing molecular weight. The Avrami equation poorly describes the isothermal crystallization of PPS. Lamellar crystallization was observed for the lowest molecular weight sample. For the other, higher molecular weight polymers the Avrami exponent is always between 2 and 3, suggesting development of distorted spherulites with heterogeneous nucleation. The temperature dependence of the solid and melt heat capacities have been determined. The solid specific heat capacity did not exhibit a molecular weight dependence. The heat capacity increase at the glass transition, T g , has been calculated to be 28.1 J°C −1 mole −1 . The equilibrium melting point of PPS has been estimated to be 348.5°C using the Hoffman–Weeks method. The T g of PPS increases with molecular weight. The T g of the highest molecular weight evaluated is 92.5°C. A DMA relaxation peak corresponding to the onset of the phenylene ring rotation occurs at −92°C. Only the highest molecular weight could be quenched to a completely amorphous state.