Thermographic study of the low-temperature behaviour of polydimethylsiloxanes

Yagfarov, M.Sh.; Ionkin, V.S.

doi:10.1016/0032-3950(68)90381-x

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…The literature values are diverse and range from 15.8 J/g to 36 J/g. [3,4,7,9,11,16,18,22] It has been reported that DH m for completely crystallized PDMS is 36.7 J/g. [4,6] Our lower heat of fusion can be ascribed to a lower crystallinity resulting from the higher molecular weight sample, …”

Section: Polymer Crystallinity In Dry Pdmsmentioning

confidence: 99%

Sorption of Organic Solvents in Poly(Dimethyl Siloxane) Membrane. II. Effect of Sorption on the Polymer Crystals upon Cooling

Lue

Yang

Chang

2006

Journal of Macromolecular Science, Part B

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Polymer crystalline properties in poly(dimethyl siloxane) (PDMS) film after solvation by various solvents was determined using low temperature differential scanning calorimetry (DSC). At various solvent uptake levels, the crystalline thermal properties of the solvated polymer were modified to different extents as revealed by the shifts in crystalline melting point (T m ) and its enthalpy (DH m ). Water uptake in PDMS was very limited (,0.01 g/g) and T m did not significantly change during the sorption process. For toluene and cyclohexane penetrants, T m moved toward a much lower temperature depending on the sorption levels. At low solvent uptakes, the T m values decreased linearly with solvent uptakes due to formation of a miscible phase. Beyond a threshold, the T m remained stable and an additional penetrant fusion peak appeared, implying the onset of a microphase separation phenomenon. The DH m values for the swollen membranes were decreased, with the exception of the water penetrant. This indicates that a lower percentage of polymer chains were involved in the crystalline domain for swollen PDMS.

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Section: Polymer Crystallinity In Dry Pdmsmentioning

confidence: 99%

Sorption of Organic Solvents in Poly(Dimethyl Siloxane) Membrane. II. Effect of Sorption on the Polymer Crystals upon Cooling

Lue

Yang

Chang

2006

Journal of Macromolecular Science, Part B

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Glass Transition Temperatures of Polymers

Andrews

Grulke

1999

The Wiley Database of Polymer Properties

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VI-244 4.6. Poly(benzimidazoles) VI-245 4.7. Poly(benzothiazinophenothiazines) VI-245 4.8. Poly(benzothiazoles) VI-245 4.9. Poly(benzoxazlnes) VI-245 4.10. Poly(benzoxazoles) VI-245 4.11. Poly(carboranes) VI-245 4.12. Poly(dibenzofurans) VI-246 4.13. Poly(dioxoisoindolines) VI-246 4.14. Poly(fluoresceins) VI-247 4.15. Poly(furan tetracarboxylic acid diimides) VI-247 4.16. Poly(oxabicyclononanes) VI-247 4.17. Poly(oxadiazoles) VI-248 4.18. Poly(oxindoles) VI-248 4.19. Poly(oxoisoindolines) VI-248 4.20. Poly(phthalazines) VI-248 4.21. Poly(phthalides) VI-248 4.22. Poly(piperazines) VI-248 4.23. Poly(piperidines) VI-249 4.24. Poly(pyrazinoquinoxalines) VI-249 4.25. Poly(pyrazoles) VI-249 4.26. Poly(pyridazines) VI-249 4.27. Poly(pyridines) VI-249 4.28. Poly(pyromellitimides) VI-249 4.29. Poly(pyrrolidines) VI-250 4.30. Poly(quinones) VI-250 4.31. Poly(quinoxalines) VI-250 4.32. Poly(triazines) VI-252 4.33. Poly(triazoles) VI-252 Table 5. Copolymers VI-252 G. References VI-253 A. INTRODUCTIONAmorphous (noncrystalline) polymeric solids are either glasses or rubbers. A glassy polymer lacks long range order, and is below the temperature at which molecular motions take place on the time scale of the experiment. A rubbery polymer is above the temperature at which molecular motions take place on the time scale of the experiment. The glass transition temperature, T g , is the critical temperature that separates glassy behavior from rubbery behavior. Many amorphous solids, including polymers, organic liquids, biomaterials, some metals and alloys, and inorganic oxide glasses, exhibit glass transition temperatures. The dramatic change in the local movement of polymer chains at T g leads to large changes in a host of physical properties. These properties include density, specific heat, mechanical modulus, mechanical energy absorption, dielectric coefficients, acoustical properties, viscosity, and the rate of gas or liquid diffusion through the polymer, to name a few. Any of these properties can be used, at least in a crude manner, to determine T g . References page VI -253 Specific volume Gl assCrystal l i zati on vol ume change Li qui d

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