Thermal stability indices for polymeric materials based on energy considerations

Reich, Leo; Levi, David W.

doi:10.1002/macp.1963.020660110

Cited by 135 publications

(40 citation statements)

References 5 publications

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“…Below are shown the expressions of the reduced time, some of which have already been calculated in the literature.18) (i) If the temperature is maintained at T from time 0 to time t : (12) (ii) If the temperature is raised from T1 to T2 at the rate of a and cooled from T2 to T3 at the rate of b : (13) (iii) If the temperature is changed from T, to T2 according to Eq. 14: (14) ( 15) where : …”

mentioning

confidence: 99%

A New Method of Analyzing Thermogravimetric Data

Ozawa¹

1965

Bulletin of the Chemical Society of Japan

6,153

2,173

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A new method of obtaining the kinetic parameters from thermogravimetric curves has been proposed. The method is simple and applicable to reactions which can not be analyzed by other methods. The effect of the heating rate on thermogravimetric curves has been elucidated, and the master curve of the experimental curves at different heating rates has been derived. The applications of the method to the pyrolyses of calcium oxalate and nylon 6 have been shown ; the results are in good agreement with the reported values. The applicability of the method to other types of thermal analyses has been discussed, and the method of the conversion of the data to other conditions of temperature change has been suggested. From these discussions, the definition of the thermal stability of materials has been criticized.

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confidence: 99%

A New Method of Analyzing Thermogravimetric Data

Ozawa¹

1965

Bulletin of the Chemical Society of Japan

6,153

2,173

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“…Weight losses of 50 wt.% in the case of PVA are recorded at 335 0 C, and in the case of copolymers at 305-327 0 C. The copolymers A, B, C that contain a higher content of aspartic acid in the synthesis (0.075 moles) present a better thermal stability than D, E, F ones, these results suggest that aspartic acid (trifunctional monomer) can lead to a more advanced grafting degree in copolymers during synthesis. The activation energy (Ea) and reaction order (n) were determined by Coats-Redfern method [28][29][30] on T i -T f temperature interval. The activation energy as a function of the conversion degree of the thermal decomposition processes (Fig.…”

Section: Figmentioning

confidence: 99%

Biodegradable poly(vinyl alcohol-lactic acid-aspartic acid) copolymers

Tudorachi

Lipşa

2009

E-Polymers

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Abstract:The aliphatic polyesters: polylactides (PLA), polyglycolides (PGA), poly( -caprolactone) (PCL) as well as their copolymers especially, poly(lactide-coglycolide) (PLGA), poly(vinyl alcohol) (PVA), chitosan, dextran and starch occupy first place among biodegradable, biocompatible and non-toxic polymers. PVA, with different molecular weights, hydrolysis degree, tacticity, crystallinity, and due to the abundance of pendant hydroxy groups in the backbone is capable of several grafting and cross-linking. The present study concerns the synthesis of graft copolymers poly(vinyl alcohol) with lactic acid (LA) and aspartic acid (Asp). The modification reaction of poly(vinyl alcohol) with lactic and aspartic acid was achieved by solution polycondensation using dioxane/water (3/1) as solvent mixture, different molar ratios PVA/LA/Asp and manganese acetate as catalyst: Mn(CH 3 COO) 2 4H 2 O. The copolymers were characterized by FTIR, 1 H-NMR, thermal stability (DSC, TG), elemental analysis, wide angle X-ray diffraction (WAXD). The average particle size and zeta potential for aqueous dispersions of copolymers, solubility in organic solvents and biodegradation testing on agar-agar medium inoculated with a fungus Chaetomium globosum class MO5 stock, were studied.

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“…The thermal degradation of UP-DIs can be estimated with kinetic parameters such as activation energy (E a ), pre-exponential factor (A) and reaction order (n) [26][27][28][29][30]. There are a number of methods for calculation of these kinetic parameters.…”

Section: Activation Energies (E a )mentioning

confidence: 99%

Flame retardance and thermal properties of a novel phosphorus-containing unsaturated polyester resin/SiO2 hybrid nanocomposite

et al. 2009

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A novel phosphorus-containing unsaturated polyester resin/SiO 2 hybrid nanocomposite was prepared from the in-situ curing of unsaturated polyester resin (UP) and triethoxysilane (DI) which was synthesized from the nucleophilic addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and 3-(trieoxysilyl) isocyanate(icteos). The formation of unsaturated polyester resin/SiO 2 hybrid nanocomposite (UP-DI) was confirmed by infrared spectra (FTIR) and scanning electron microscopy (SEM). With the increase of DI contents, the limiting oxygen index (LOI) value of the cured UP-DIs was raised from 19 to 29, suggesting a significant improvement in flame retardance. The improved flame retardance could also be revealed by the variations of weight and morphology of char residues. Thermogravimetric analysis (TGA) both in air and in nitrogen was used to estimate mechanism of thermal degradation and activation energy (E a ) of different degree of conversion (α) was calculated by Ozawa's method. The UP-DI containing 10%DI (UP-DI10) had higher E a than the pure UP as α>5% because the degradation mechanism was altered by the incorporation of DI.

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Thermal stability indices for polymeric materials based on energy considerations

Cited by 135 publications

References 5 publications

A New Method of Analyzing Thermogravimetric Data

A New Method of Analyzing Thermogravimetric Data

Biodegradable poly(vinyl alcohol-lactic acid-aspartic acid) copolymers

Flame retardance and thermal properties of a novel phosphorus-containing unsaturated polyester resin/SiO2 hybrid nanocomposite

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