Neuere physikalische Untersuchungen an Hochpolymeren

Hendus, H.; Schnell, Gg.; Thurn, H.; Wolf, Karl

doi:10.1007/bfb0110723

Cited by 32 publications

(12 citation statements)

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“…The earliest relaxation map known to us is that of T h~r n ,~ (Hendus et al 59) and is actually in the form of a log f vs. T("C) plot. It contains a considerable amount of diverse types of data from dynamic mechanical t o NMR to ultrasonics, covering the frequency range from 10-1 to lo7 Hz.…”

Section: A Relaxation Map For Pibmentioning

confidence: 99%

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Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Boyer¹,

Enns²

1986

J of Applied Polymer Sci

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SynopsisLinear regression analysis studies with residuals of heat capacity vs. temperature C C , vs. T) data above the glass transition temperature (T,) for polyisobutylene (PIB) T,, is plausible in terms of the Frenkel-Baranov phase dualism mechanism. A complete relaxation map (log f vs. 1IT) has been assembled with frequencies from lo-* to 1O'O Hz and temperatures from 150 to 500 K. It shows T p , T,, TI, and methyl group rotation, all based on data in the literature. The molecular weight dependence of T, and T,, and the low resiliency of butyl rubber as it relates to T,, are discussed in the appendices.

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Section: A Relaxation Map For Pibmentioning

confidence: 99%

“…This may well represent a merged T,, -Tlp locus. The high frequency values of T,, are from the ultrasonic loss points originally collected by T h~r n~~ and Hendus et al 59 Since they were estimated from plots, they show scatter. They seem to fall on the tan 6 line for T,,.…”

Section: A Relaxation Map For Pibmentioning

confidence: 99%

Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Boyer¹,

Enns²

1986

J of Applied Polymer Sci

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“…2 a uberein. Die beiden G"-Maxima wurden in 20) als die Glastemperaturen einer aniorphen &Phase und einer ebenfalls amorphen y-Phase gedeutet. Nach den nun vorliegenden Untersuchungen ist diese Aufspaltung in 2 Maxima jedoch lediglich eine Folge der wahrend des Aufheizens erfolgenden Kristallisation.…”

Section: Experimentellesunclassified

Schmelzverhalten, struktur und kristallinität von 6‐polyamid

1971

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ZUSAMMENFASSUNG:Abgeschrecktes, nahezu amorphes 6-Polyamid wurde durch Tempern (10 Miu. bis 2000Stdn.) bei 46 5 T, < 225°C kristallisiert. An diesen Proben wurden Schmelzpunkt, Schmelzwarme, spezifisches Volumen, Kristallstruktur und Langperiode gemessen.Die bei T, < 150°C gebildeten Kristalle mit y-Struktur sind so instabil, da13 ihr Schmelzpunkt mit den zur Verfugung stehenden Aufheizgeschwindigkeiten nicht ermittelt werden kann. Der Schmelzpunkt der bei T, > 190°C entstandenen Kristalle rnit iiberwiegend cc-Struktur liegt nach Messungen in Abhangigkeit von der Aufheizgeschwindigkeit je nach Tempertemperatur uud Temperdauer zwischen 208 und 250°C.Rei Proben mit a-Struktur besteht ein anderer Zusammenhang zwischen Schmelzwarme und spezifischem Volumen als bei Proben mit y-Struktur. Das spezifische Volumen va der amorpheu Bereiche von in or-Struktur kristallisierten Proben ist kleiner (0,901 cm3/g) als bei in y-Struktur kristallisierten Proben (0,917 cm3/g). Der Gleichgewichtsschmelzpunkt der a-Struktur betragt 260°C. Die freie Oberflachenenergie 0 : wurde zu 47 erg/cm2 ermittelt. Der unendlich groBe 6-Polyamidkristall mit a-Struktur besitzt eine Schmelzwarme zwischen 55 und 64 cal/g, je nachdem, welche der in der Literatur angegebenen Xxistalldichten als richtig angesehen wird. Eine genaue Kristallinitatsbestimmung kann bisher weder aus dem spezifischen Volumen noch aus der Schmelzwarme durchgefuhrt werden.In den DSC-Kurven der getemperten Proben treten oberhalb der Tempertemperatur die bekannten endothermen Vormaxima a d . Untersuchungen in Abhangigkeit von der Aufheizgeschwindigkeit und an methoxymethylierten Proben zeigen, da13 die oberhalb bzw. unterhalb T, = 160°C entstandenen Vormaxima unterschiedliche Ursachen haben. SUMMARY:Melting point, heat of fusion, specific volume, crystal structure, and X-ray small angle period of 6-Polyamide have been measured on samples annealed a t 46 5 T, 5 225°C for 10 min to 2000 hrs from the nearly amorphous quenched state.The crystals grown at T, < 150°C with y-structure are so instable, that their melting point cannot be determined within the available heating rates. Depending on annealing temperature and annealing time the zero-entropy-production melting point of cc-crystals is varied between 208 and 25OoC. The relation between heat of fusion and specific volume is different for samples with a-and y-structure. The specific volume v. of the non-crystalline regions depends on the structure of the crystals. It is smaller for samples with cc-structure (0.901 cm3/g) than for samples with y-structure (0.917 cm3/g). The equilibrium melting point of the a-structure is 260°C. For the free surface energy cz a value of 47 erg/cm2 has been determined. The infinitely large 6-polyamide crystal with a-structure has a heat *) Revidiertes Mauuskript vom 17. November 1970. 31K.-H. ILLERS und H. HABERKORN of fusion between 55 and 64 cal/g, depending on which of the different crystal densities, that have been reported in literature, will be accepted. An exact determination of crystallinity ...

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“…Infrared spectroscopy was chosen as a key structure identification experiment since several studies have demonstrated that a variety of quantitative morphological information may be obtained. These include the percent crystallinity (5,6), the extent of chain branching (7,8) the second moment of the orientation of the crystalline and moncrystalline chain elements (9,10), and the conformation of the noncrystalline chain elements (11). Working with our carefully prepared samples, several new features have emerged from the infrared studies that are reported here and have also proved quite unique in further developments of constitutive structure-property relations (4).…”

Section: Introductionmentioning

confidence: 77%

Structural characterization of linear polyethylene by infrared spectroscopy

Wedgewood¹,

Seferis²

1983

Pure and Applied Chemistry

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The structural features exhibited by a series of unoriented and uniaxially oriented linear polyethylene samples prepared under carefully controlled conditions have been examined by polarized and nonpolarized infrared experiments. Specifically, structural arrangements associated with the noncrystallime phase of the polymer have been examined both experimentally and theoretically. Experimentally, it was observed that the conformational arrangement of the noncrystalline phase was insensiive to density for samples whose bulk density was less than 0.96 g/cm .

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Neuere physikalische Untersuchungen an Hochpolymeren

Cited by 32 publications

References 94 publications

Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Schmelzverhalten, struktur und kristallinität von 6‐polyamid

Structural characterization of linear polyethylene by infrared spectroscopy

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Neuere physikalische Untersuchungen an Hochpolymeren

Cited by 32 publications

References 94 publications

Regression analysis studies of polymer transitions II. TII from specific heat and other data for polyisobutylene

Regression analysis studies of polymer transitions II. TII from specific heat and other data for polyisobutylene

Schmelzverhalten, struktur und kristallinität von 6‐polyamid

Structural characterization of linear polyethylene by infrared spectroscopy

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Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene