Specific heats of poly (vinyl chloride) compositions

Dunlap, L. H.

doi:10.1002/polc.5070300160

Cited by 5 publications

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“…The case of slightly plasticized poly(vinyl chloride) (PVC) is interesting in that it constitutes not only a typical plasticized system in the usual sense, but also it behaves quite unusually in the glassy state below the glass transition temperature Tg. That is to say, one observed (1) an increase of elastic modulus, (2) appearance of brittleness (a marked decrease in impact strength and ultimate elongation), (3) disappearance of the secondary (/3) dispersion, (4) invalidity of the additivity volume law, 1 • 2 (5) decrease of the thermal coefficient of specific volume and (6) an anomalous behavior of the heat capacity,3 in PVC containing relatively small amounts of plasticizers.…”

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Antiplasticization in the Slightly Plasticized Poly(vinyl chloride)

Kinjo

Nakagawa

1973

Polym J

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The dynamic mechanical moduli of slightly (0-16 wt96) plasticized poly(vinyl chloride) were measured by the method of free damped oscillation in the temperature range from -180 to + 100°C. The added plasticizers are tricresyl phosphate (TCP), butyl benzyl phthalate (BBP), dioctyl phthalate (DOP), dibutyl sebacate (DBS) and dioctyl sebacate (DOS). Two dispersion regions (a and /3) are observed in the case of poly(vinyl chloride) and they are influenced by addition of plasticizers. The a-dispersion shifts to the lower temperature side and broadens with increasing plasticizer content. These effects are mainly dependent upon the plasticizer species, and of the above plasticizers their plasticizing ability decreases in the order of DOS> DBS>DOP>BBP>TCP. The /3-dispersion, whose activation energy was estimated to be 14.3 kcal/mo!, first begins to disappear from the higher temperature side with increasing plasticizer content and ultimately vanishes. This effect scarcely depends upon the plasticizer species.Young's moduli of these samples were measured at -20-+40°C from observing the tensile stress relaxation. The modulus vs. plasticizer content curve shows a maximum. This is an example of "antiplasticization." The ability of additives to provoke antiplasticization decreases in the reverse order of plasticizing ability, that is, in the order of TCP>BBP>DOP>DBS>DOS.KEY WORDS Antiplasticization / Poly(vinyl chloride)/ Plasticizer/ Viscoelasticity / Polymer

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Antiplasticization in the Slightly Plasticized Poly(vinyl chloride)

Kinjo

Nakagawa

1973

Polym J

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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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