Thermodynamics of addition polymerisation. Part 2. The heat capacity, entropy and enthalpy of isotatic poly (4‐methyl‐1‐pentene)

Melia, Tom; Tyson, A.

doi:10.1002/macp.1967.021090109

Cited by 13 publications

(1 citation statement)

References 14 publications

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“…No evidence for additional crystallization was seen in the thermograms obtained during heating to the melt. As observed previously for PMP, , and often for semicrystalline polymers in general, differential scanning calorimetry does not provide unambiguous evidence for the presence of a glass transition.…”

Section: Resultsmentioning

confidence: 53%

Structure and Temperature-Dependent Properties of Poly(4-methyl-1-pentene) Fibers

Reddy¹,

Desai²,

Abhiraman³

et al. 1997

Macromolecules

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The origin of a dramatic loss of tensile strength in poly(4-methyl-1-pentene) [PMP] above a major dynamic mechanical transition that occurs around 45 °C is explored. The usual mechanisms associated with loss of strength in polymers are shown to be absent in this case. Viscous dissipation disappears almost completely during deformation of PMP above the transition of interest here. A thermodynamic analysis of reversible deformation is shown to provide remarkably good predictions of the work of rupture under such conditions. The thermorheological responses of PMP suggest that the transition of concern here is not accompanied by the onset of rapid backbone motions but by pendant group motions. Indeed, 2D wideline separation (WISE) NMR, which correlates dynamics (via 1 H widelines) with structure (via 13 C chemical shifts), clearly reveals that this transition is primarily accompanied by the onset of rapid pendant group motions. Such motions, coupled with the relatively large inter-backbone distances in PMP, provide the conditions necessary for elimination of viscous dissipation. These findings require refinement of the previously held view that the transition around 45 °C in PMP denotes a glass transition associated with the onset of rapid backbone segmental motions.

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Section: Resultsmentioning

confidence: 53%

Structure and Temperature-Dependent Properties of Poly(4-methyl-1-pentene) Fibers

Reddy¹,

Desai²,

Abhiraman³

et al. 1997

Macromolecules

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Heats and Entropies of Polymerization, Ceiling Temperatures, Equilibrium Monomer Concentrations, and Polymerizability of Heterocyclic Compounds

Léonard

1999

The Wiley Database of Polymer Properties

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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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Thermodynamics of addition polymerisation. Part 2. The heat capacity, entropy and enthalpy of isotatic poly (4‐methyl‐1‐pentene)

Cited by 13 publications

References 14 publications

Structure and Temperature-Dependent Properties of Poly(4-methyl-1-pentene) Fibers

Structure and Temperature-Dependent Properties of Poly(4-methyl-1-pentene) Fibers

Heats and Entropies of Polymerization, Ceiling Temperatures, Equilibrium Monomer Concentrations, and Polymerizability of Heterocyclic Compounds

Glass Transition Temperatures of Polymers

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