Glass Transition Temperatures of Polymers

Abstract

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

Melting and glass transitions in paraffinic and naphthenic oils

“…This is coincidentally the temperature region covered by the T g of asphaltenes [9,11]. Similarly, the extrapolation to 100% saturates or 0% aromatics leads to a T g of -142 °C to -152 °C, relatively close to the T g of long chain n-paraffins (polyethylene) at -125 °C [33]. The low extrapolated T g of the saturates vs polyethylene is likely a reflection of their low molecular weight and their greater segment mobility compared to long-chain paraffins.…”

Hybrid membrane materials comprising organic polymers with rigid dispersed phases

“…This T g -elevation phenomenon is also postulated to occur, in the absence of other effects, in semi-crystalline polymers with proportionate increases in crystallinity (Andrews and Grulke, 1999). The results suggest that the presence of an insert can affect the fundamental properties (such as T g ) of the polymer matrix when good segmental-level attachment exists between these two phases.…”

Synthesis of Poly(4‐vinylpyridine) Thin Films by Initiated Chemical Vapor Deposition (iCVD) for Selective Nanotrench‐Based Sensing of Nitroaromatics

“…Therefore, the kinetic chain length was approximately 13.4, and the material can legitimately be considered an oligomer. While it is possible to increase the molecular weight using iCVD, [24][25][26] the lower molecular weights obtained here are desirable since they result in lower glass transition temperatures (T g ) [27] and, therefore, higher diffusion constants. Higher diffusion coefficients are desirable since diffusion control the sensors' response times.…”