Dynamic thermal decomposition of linear polymers and its study by thermo analytical methods

Shlensky, O. F.; Vaynsteyn, E. F.; Matyukhin, A. A.

doi:10.1007/bf02331766

Cited by 23 publications

(11 citation statements)

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“…In so doing, the rate of decrease in mass is higher than that predicted by the Arrhenius equation corresponding to low temperatures [5][6][7]. An especially abrupt increase in the rate of transformation was observed at temperatures close to T l ; this is due to the weakening of intermolecular interaction (IMI) with increasing volume of CS, because the deformations of chemical (valence) bonds are negligible.…”

Section: Kinetic Relationsmentioning

confidence: 89%

“…These conditions are observed in the "thermal probe" method [3,4,10] and other contact TA methods [5][6][7], which enables one to investigate the kinetics of decomposition of CS at high temperatures inaccessible for many other standard TA methods. The conductive heating is characterized by higher rates of sample temperature increase compared to the convective method of delivering heat to crucibles in conventional TA methods.…”

Section: Experimental Datamentioning

confidence: 94%

“…This omission is largely caused by the absence of reliable methods of experimental determination of the limit of phase state (LPS), because the numerical determination of the conditions of thermodynamic stability of CS from equations of state [8,9] is characterized by low accuracy. The advent in the 1980s of methods of pulsed heating such as the "thermal probe" method [3,4] and contact methods of thermal analysis (TA) [5,6] enabled one to actually determine the position of LPS by the temperatures of attainable superheating T l of volatile and nonvolatile CS including polymer systems [4][5][6][7]10]. The development of TA methods opened up prospects for the construction of physical and mathematical models of front processes in view of temperature constraints (T < T l ).…”

Section: Introductionmentioning

confidence: 99%

“…Interest in this problem is caused by the practical importance of the results of investigations in various fields of modern engineering such as aviation, rocketry, chemical technology, and so on. Many a mathematical model of propagation of heat and, in particular, of front processes in nonvolatile thermally unstable CS fail to include the possibility of loss of thermodynamic stability at high temperatures attained as a result of rapid (10 3 to 10 5 K/s) heating and at high values of energy input [3][4][5][6][7]. The region of variation of CS temperature in simulation is taken to be unlimited (as in the gas phases): 0 < T < ∞.…”

Section: Introductionmentioning

confidence: 99%

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The variation of the parameters of front processes of thermal decomposition of condensed systems in the vicinity of the limit of thermodynamic stability

Shlenskii

2006

High Temp

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Section: Kinetic Relationsmentioning

confidence: 89%

Section: Experimental Datamentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The variation of the parameters of front processes of thermal decomposition of condensed systems in the vicinity of the limit of thermodynamic stability

Shlenskii

2006

High Temp

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“…When the reaction is complete, a polymeric system can stand up to 100 heating pulses with reproducible values of T*, i.e., without any irreversible destruction of the boundary layer, at f m = 0.5 Hz.…”

Section: Polymerization and Curingmentioning

confidence: 99%

Heat pulse monitoring of curing and polymer–gas systems

Скрипов

Puchinskis

Begishev

et al. 1994

J of Applied Polymer Sci

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SYNOPSISAn implantable thermal probe is used to study the reaction of molten polymers and curing systems to pulse heat release. At the heating rates T 2 5 -lo5 K/s, a polymer system shows the response to pulse heating that is confined in time and reproducible with respect to temperature. This response is related to the abrupt change in the conditions of the contact between the probe and a substance. The temperature of the response T* is determined by the polymer properties and depends on the pressure and T. The pulse thermal probe method, which includes two measuring procedures, complementing each other, has been used to monitor a number of processes in polymeric systems. The variation of the values of T* and the thermal activity of a polymer is compared with the variation of its molecular weight (A& -10'-lo6), the molecular weight distribution, and the concentration of a low molecular weight component. The method allows one to trace the kinetics of polymerization and curing and the kinetics of dissolution of volatile impurity and polymer devolatilization, and to determine the limit of supersaturation of gas solutions in molten polymers. The pulse repetition frequency is changed from 0.1 to 1 Hz. The heated volume of a substance is mm3. 0 1994 John Wiley & Sons, Inc. INTRODUCTIONThe methods of the study of the substance properties and characteristics of processes based on the recording and analysis of the system response to some perturbation ( mechanical, acoustic, electrical) have found a wide application for polymers.' We used for these purposes the method of pulse heating of a substance on the surface of a wire probe2s3 and revealed the response confined in time and reproducible with respect to temperature of a polymeric system to heat release. The nature of this response is related to an abrupt violation of the conditions of the probe contact with a substance. The temperature of the response depends on the instantaneous composition and physicochemical properties of a substance. Its value is above the traditional temperature range for experiments with polymers. By the character of the response, the observed phenomenon is similar to that of spontaneous nucleation in superheated low * To whom correspondence should be addressed. , but shall discuss the possibilities of the practical use of the method of pulse heating for the evaluation of a number of parameters of polymeric systems and processes, in particular, the value of the molecular mass and polydispersity, kinetics of curing, kinetics of dissolution or removal of volatile impurities, and the boundaries of the stability of a condensed state of an oligomer supersaturated with a gas. The prospects of effective use of the method are based on its speed, microquantity of the analyzed substance, independence of the observed parameter (T* ) on the medium temperature, and compactness and noise im-munity of the equipment employed. The characteristic time of heating is of the order of 10-4-10-5 s, and the heated volume is of the order of 10 p4 mm3. The pulse repetit...

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Structure–properties‐performance relationships in complex epoxy nanocomposites: A complete picture applying chemorheological and thermo‐mechanical kinetic analyses

Jouyandeh

Jazani

Navarchian

et al. 2021

J of Applied Polymer Sci

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Herein the kinetics of network formation (cross‐linking) and network degradation (thermal decomposition) in a complex system based on epoxy resin reinforced with hyperbranched amino polymer‐functionalized nanoparticles (HAPF) were discussed. Five classes of nanoparticles, that is, nano‐SiO2, halloysite nanotubes (HNTs), HNTs@nano‐SiO2 core/shell, HAPF/nano‐SiO2, HAPF/HNTs@nano‐SiO2 core/shell were loaded at 0.5, 1.0, 2.0 (optimal loading among prepared samples), and 5 wt% were examined. Parameters of the cure kinetics and degradation were correlated, and the mechanical properties were interpreted in terms of microstructure and rheological analyses. The isothermal chemorheological cure kinetics study (60, 70, and 80°C) revealed a low activation energy for epoxy/HAPF/HNTs@nano‐SiO2 core/shell nanocomposite (72.21 kJ/mol), compared with the blank epoxy (79.99 kJ/mol). Correspondingly, gel time of the system decreased from 1040 to 515 to 237 s upon isotherms of 60, 70, and 80°C, respectively. Tensile strength was also increased vividly (ca. 32%), possibly due to the strong interfacial adhesion, which reflected in an induced shear yielding. Nitrogen‐mediated thermal decomposition kinetics suggested an average degradation activation energies of ca. 150 and 210 kJ/mol for the assigned nanocomposites and the blank epoxy, respectively. Overall, there was a complete agreement between the kinetics of network formation and network degradation in the studied epoxy nanocomposite. This work enables understanding of structure‐properties‐performance in complex epoxy nanocomposites.

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Dynamic thermal decomposition of linear polymers and its study by thermo analytical methods

Cited by 23 publications

References 1 publication

The variation of the parameters of front processes of thermal decomposition of condensed systems in the vicinity of the limit of thermodynamic stability

The variation of the parameters of front processes of thermal decomposition of condensed systems in the vicinity of the limit of thermodynamic stability

Heat pulse monitoring of curing and polymer–gas systems

Structure–properties‐performance relationships in complex epoxy nanocomposites: A complete picture applying chemorheological and thermo‐mechanical kinetic analyses

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