Mechanical secondary relaxation effects in polysulfone

Baccaredda, M.; Butta, E.; Frosini, Vittorio; Petris, S. De

doi:10.1002/pol.1967.160050624

Cited by 34 publications

(15 citation statements)

References 3 publications

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“…The γ relaxation of polymers such as polyethylene, poly(methyl methacrylate), and polystyrene can be attributed to the molecular motions of short branching or the local motion of chains existing on the crystallite surface, or both. For rigid aromatic polymers the low‐temperature mechanical relaxation can be attributed to the local motion of aromatic units in the main chain 17–19. The γ‐relaxation peak of the crosslinked sample broadened, which also could be a result of the local motion of cyclic units in the main chain, and the β‐relaxation shifts to a higher temperature could be from an increasing glass‐transition temperature ( T g ).…”

Section: Resultsmentioning

confidence: 99%

“…For rigid aromatic polymers the low- temperature mechanical relaxation can be attributed to the local motion of aromatic units in the main chain. [17][18][19] The ␥-relaxation peak of the crosslinked sample broadened, which also could be a result of the local motion of cyclic units in the main chain, and the ␤-relaxation shifts to a higher temperature could be from an increasing glass-transition temperature (T g ). It is known that, in highly crosslinked materials, the T g and the modulus at the rubbery plateau are related to the crosslink density.…”

Section: Dynamic Viscoelastic Propertiesmentioning

confidence: 99%

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Radiation crosslinking of poly(butylene succinate) in the presence of low concentrations of trimethallyl isocyanurate and its properties

Suhartini

Mitomo

Nagasawa

et al. 2003

J of Applied Polymer Sci

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Poly(butylene succinate) (PBS) with different molecular weights was irradiated using an electron beam (EB) in the presence of polyfunctional monomers at ambient temperature. Five polyfunctional monomers were used in this work. The highest amount of gel fraction was achieved when PBS was blended with trimethallyl isocyanurate (TMAIC). The amount of TMAIC introduced strongly influenced the amount of resulting gel. It was determined that the crosslinked PBS sample containing 1% TMAIC had a higher glass-transition temperature than did the original PBS. It was also observed that the presence of crosslinking bonds in the irradiated PBS greatly improved its heat stability and diminished its ability to biodegradate. Accordingly, it can be concluded that crosslinked PBS in the presence of TMAIC significantly improved its heat resistant properties.

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Section: Resultsmentioning

confidence: 99%

Section: Dynamic Viscoelastic Propertiesmentioning

confidence: 99%

Radiation crosslinking of poly(butylene succinate) in the presence of low concentrations of trimethallyl isocyanurate and its properties

Suhartini

Mitomo

Nagasawa

et al. 2003

J of Applied Polymer Sci

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“…This relaxation temperature and the magnitude of tan δ are not remarkably changed on the dried film. Therefore, this relaxation is not influenced by water uptake as reported 9, 15–17. This kind of relaxation has not been reported on the spectra of PEEK and noncrystalline PEEK, but the relaxation at −80°C was observed as the relaxation arising from the aryl ether group, called mechanical secondary relaxation or low‐temperature mechanical relaxation 17, 35.…”

Section: Resultsmentioning

confidence: 59%

“…These results suggest that movement of polymer chains in the glassy state is restricted by the irradiation because of the structural change of F‐PEK to a more rigid structure. This kind of phenomenon was also characterized on the irradiated PEEK film and was never observed on PS and PES 15–17. The lowering of the glass transition of PS and PES was accounted for by lowering of the cohesive energy density attributed to polymer chain scission.…”

Section: Resultsmentioning

confidence: 77%

“…In the last few decades many aromatic polymers showing good resistance to degradation by high‐energy radiation have been developed to be used as materials in high‐energy radiation environments, such as those found in the nuclear and aerospace industries 4–7. Among them, poly(ether ether ketone)s (PEEK)4, 8–11 and polyamides6 exhibit better resistance than that of other aromatic polymers such as poly(sulfone)s (PS),12–14 poly(ether sulfone)s (PES),13–18 and polyesters 14, 19. However, their potential is less than that of polyimides represented by Kapton 20–24…”

Section: Introductionmentioning

confidence: 99%

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Influence of electron beam irradiation on properties of fluorine‐containing poly(aryl ether ketone)s

Kimura

Tabuchi

Nishichi

et al. 2003

J of Applied Polymer Sci

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ABSTRACT:The influence of electron beam irradiation on the properties of fluorine-containing poly(aryl ether ketone)s (F-PEK), derived from 2,3,4,5,6-pentafluorobenzoic acid, was examined. Irradiation was performed with an electron beam at a dose of 3.63 ϫ 10 3 Gy s Ϫ1 for which the corresponding doses were 29.0, 51.0, and 94.5 MGy. Tensile strength at break increased up to a dose of 29.0 MGy and then decreased very slightly with irradiation. Elongation at break was more susceptible to irradiation and decreased drastically to one tenth at a dose of 29.0 MGy. Young's modulus was enhanced by the irradiation. F-PEKs were changed from elastic materials to strong and brittle materials by irradiation. Relaxation of the viscoelastic property shifted toward higher temperature by irradiation. These tensile and viscoelastic property changes were attributed to the formation of a bulkier and more rigid structure by crosslinking. The fluorine atoms attached to the 1,4-phenylene moiety in F-PEKs were surprisingly susceptible to the irradiation and were completely lost at a dose of 29.0 MGy. The -electron conjugated aromatic structure was concurrently developed during irradiation. Further, polar functional groups such as carboxyl group and ester group were generated by chain scission and rearrangement. The F-PEKs retained their good transparency and the thermal stability was significantly improved after irradiation.

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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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Mechanical secondary relaxation effects in polysulfone

Cited by 34 publications

References 3 publications

Radiation crosslinking of poly(butylene succinate) in the presence of low concentrations of trimethallyl isocyanurate and its properties

Radiation crosslinking of poly(butylene succinate) in the presence of low concentrations of trimethallyl isocyanurate and its properties

Influence of electron beam irradiation on properties of fluorine‐containing poly(aryl ether ketone)s

Glass Transition Temperatures of Polymers

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