Heat capacities of high melting polymers containing phenylene groups

Cheng, Stephen Z. D.; Lim, Stephanie I.; Judovits, Lawrence; Wunderlich, Bernhard

doi:10.1016/0032-3861(87)90313-2

Cited by 49 publications

(17 citation statements)

References 27 publications

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“…To evaluate C p (vibration) of PBT, we separated the 84 degrees of freedom resulting from the 28 atoms of the repeating unit into 63 group vibrations and 21 skeletal vibrations, as shown in Table 2 and detailed in Tables 3 and 4. The group vibrational frequencies were taken to be equal to those of PET, which were taken from normal‐mode calculations, fitted to experimental infrared and Raman frequencies,28, 29 and expanded by the addition of the group vibrations of the two missing CH 2  groups from polyethylene (PE); this was similar to what was done for PTT 12. The group‐vibrational frequencies are shown in Tables 3 and 4.…”

Section: Resultsmentioning

confidence: 99%

“…45 and 46, the designations of the atomic motions is approximate (see also refs. 28 and 29). The vibrations 5, 7A, 17B, 9B, 10B, 11, 18B, and 20A are most reduced in frequency because of the 1,4‐substitution.…”

Section: Resultsmentioning

confidence: 99%

“…Θ is the Einstein mode in units of kelvin, and ν the same in units of H z , as expressed by the equation in the text. All approximate group vibrational frequencies of PBT are collected from polymers that contain groups of similar chemical structures, such as PET11, 28, 29 and PTT 12…”

Section: Cp Values Of the Solid And Liquid Statesmentioning

confidence: 99%

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Heat capacity of poly(butylene terephthalate)

Pyda

Nowak-Pyda

Mays

et al. 2004

J Polym Sci B Polym Phys

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The low‐temperature heat capacity of poly(butylene terephthalate) (PBT) was measured from 5 to 330 K. The experimental heat capacity of solid PBT, below the glass transition, was linked to its approximate group and skeletal vibrational spectrum. The 21 skeletal vibrations were estimated with a general Tarasov equation with the parameters Θ1 = 530 K and Θ2 = Θ3 = 55 K. The calculated and experimental heat capacities of solid PBT agreed within better than ±3% between 5 and 200 K. The newly calculated vibrational heat capacity of the solid from this study and the liquid heat capacity from the ATHAS Data Bank were applied as reference values for a quantitative thermal analysis of the apparent heat capacity of semicrystalline PBT between the glass and melting transitions as obtained by differential scanning calorimetry. From these results, the integral thermodynamic functions (enthalpy, entropy, and Gibbs function) of crystalline and amorphous PBT were calculated. Finally, the changes in the crystallinity with the temperature were analyzed. With the crystallinity, a baseline was constructed that separated the thermodynamic heat capacity from cold crystallization, reorganization, annealing, and melting effects contained in the apparent heat capacity. For semicrystalline PBT samples, the mobile‐amorphous and rigid‐amorphous fractions were estimated to complete the thermal analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4401–4411, 2004

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Heat capacity of poly(butylene terephthalate)

Pyda

Nowak-Pyda

Mays

et al. 2004

J Polym Sci B Polym Phys

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“…For the evaluation of the vibrational heat capacity of PVME, the 30 degrees of freedom resulting from the 10 atoms of the repeating unit were separated into 21 group vibrations ( N gr = 21) and 9 skeletal vibrations ( N sk = 9), as shown in Table 2 and detailed in Table 3. The approximate group vibrational frequencies were taken to be equal to the analogous vibrations found in polypropylene (CH 2 CHCH 3 ) x , and the CH 2 OCH 2 ‐groups in polyoxyethylene,37, 38 as shown in Table 3.…”

Section: Resultsmentioning

confidence: 99%

Modelling of phenol biodegradation by Candida tropicalis immobilised in alginate gel beads

et al. 2011

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Phenol-degrading yeast Candida tropicalis were immobilised in alginate gel beads and photographed by scanning electron microscopy. Batch phenol biodegradation experiments were done in shaking flasks under varying conditions such as initial phenol concentrations and bead loadings. A mathematical model was proposed to simulate the batch phenol biodegradation process in the immobilised system, which took into account the internal and external mass transfer resistances of phenol and oxygen and the double-substrate phenol-oxygen intrinsic kinetics. The validation of this model was done by the comparison between the model simulations and the experimental measurements of phenol concentration profiles in the main liquid phase. Moreover, the time and radius courses of phenol, oxygen, and cell concentration profiles within the alginate gel beads were reasonably predicted by the proposed model.Des cellules du champignon Candida tropicalis, ayant la capacité de dégrader le phénol, ontété visualisées par microscopieà balayageélectronique, après avoirété immobilisées sur des billes gélifiées d'alginate. Des expériences de biodégradation du phénol en culture discontinue dans des flasques agités ontété réalisées dans des conditions variables, en particulier avec des concentrations initiales de phénol différentes et des charges fungiques des billes multiples. Un model mathématique de simulation du procédé de biodégradation du phénol dans le système immobilisé des billes, est ici proposé. Il tient compte des résistances internes et externes des transferts de masse du phénol et de l'oxygène. Il comprend aussi la cinétique intrinsèque du substrat phénol-oxygène. La validité du model aété assurée par la comparaison entre les simulations et les mesures expérimentales de la concentration en phénol dans la principale phase liquide. Les prédictions du model se sont avérées raisonnables, en terme de temps et de radius pour estimer la concentration en phénol, et en oxygène ainsi que les densités cellulaires nécessairesà immobiliser sur les billes d'alginate.

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“…The group vibrations were assigned using the method developed for phenylene containing polymers. 18 It involved choosing the appropriate, known 155 and 225 group vibrations of the groups that make up PEIM-12 and PEIM-22, respectively, from the earlier analyzed vibrations of poly(ethylene terephthalate), poly(1,4-phenylene), poly(etherether-ketone), and polyethylene, in addition to the CON-stretching frequencies, derived by Cheng et al 19 All remaining vibrations were combined empirically into skeletal vibrations and fitted to the experimental, skeletal heat-capacity contribution using the Tarasov eq 3.…”

Section: Thermal Properties Of Poly(ester-imide)smentioning

confidence: 97%