Studies on Thermal Decomposition Kinetics of Polyvinyl Nitrate

Abstract

Non‐isothermal TG curves for four samples of polyvinyl nitrate (PVN), having 15.71%, 14.95%, 13.34% and 11.76% nitrogen contents, were obtained at 5°C/min heating rate. The weight loss of PVN samples depends directly on their % N and occurs in three or more temperature zones. For PVN with 15.71% N (max 15.73% N in theory), the main decomposition step results in more rapid and complete weight loss than for PVN with lower % N, probably due to higher oxygen balance of the former. The TG data were subjected to kinetic analysis using a computer programme. For each decomposition step, the kinetic parameters (E and A) and the regression coefficient (r) were calculated on the basis of several kinetic models and equations consistent with the Arrhenius relationship. It was concluded that the thermal decomposition kinetics of all four PVN sample are best expressed by the Random nucleation model (Mampel unimolecular law) first‐order reaction. For the initial and slowest decomposition step, E ranged between 188 kJ/mol − 217 kJ/mol and In A between 46.88 s−1 ‐ 60.13 s−1. The In A versus E plots for all PVN samples exhibited a linear relationship, probably due to the kinetic compensation effect.

Kinetics of Scrap Tire Pyrolysis in a Conical Spouted Bed Reactor

“…[42][43][44] Type 2 causes explain the different results in the pyrolysis of cellulose and lignocellulosic materials, [45][46][47] in the pyrolysis of tire rubbers, 19 and in other reactions of thermal transformation. 30,48 Type 3 causes have been analyzed in the pyrolysis of cellulose. 49 Figure 6 shows an Arrhenius-type representation where the kinetic constants determined in this paper in a CSBR are plotted together with those previously obtained by means of thermogravimetry and fast heating microreactors.…”

“…), which is usual due to the differences in the equipment used for gas−solid contact (thermogravimetry and laboratory microreactors); and (3) differences in the kinetic model or in the methodology of kinetic data analysis and parameter calculation. Type 1 causes are frequent in studies on tire pyrolysis, and it is precisely this difference in the pyrolysis that allows for distinguishing the type of elastomer and for determining the amount of different rubbers in the tire. − Type 2 causes explain the different results in the pyrolysis of cellulose and lignocellulosic materials, − in the pyrolysis of tire rubbers, and in other reactions of thermal transformation. , Type 3 causes have been analyzed in the pyrolysis of cellulose …”

Thermal Analysis

“…Studies on ammonium nitrate employ DSC to determine the effect of particle size (305) and TG to investigate the mass loss process in the molten state (306). There are thermal analysis studies on various energetic materials containing nitrogen such as diazodinitrophenol (307), poly(vinyl nitrate) (308), and feranzao[3,4-b]piperazine (309). Catalysts have a significant effect on the thermal decomposition of certain propellants (310).…”

Kinetics of scrap tyre pyrolysis under fast heating conditions

“…Furthermore, the maximum degradation temperature of the same type of rubber under identical conditions depends on the compositions of tyre sample [37,38]. Another common result is that the kinetic constant depends on the heating velocity [39][40][41][42] or on the conversion [43]. These latter results have been explained by taking into account changes in the reaction mechanism according to temperature history.…”