Thermal characterization of HCN polymers by TG–MS, TG, DTA and DSC methods

This paper presents a thermogravimetry (TG) study of hydrogen cyanide polymers, synthesized from the reaction of equimolar aqueous solutions of sodium cyanide and ammonium chloride. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were also used to evaluate the thermal...

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Bibliographic Details
Published in:Polymer degradation and stability 2011-05, Vol.96 (5), p.943-948
Main Authors: de la Fuente, José L., Ruiz-Bermejo, Marta, Menor-Salván, César, Osuna-Esteban, Susana
Format: Article
Language:English
Subjects:
ammonia
ammonium chloride
Applied sciences
aqueous solutions
Coupled TG–MS
depolymerization
Differential scanning calorimetry
Differential thermal analysis
DSC
DTG
Dynamical systems
Dynamics
Exact sciences and technology
HCN polymers
Hydrogen cyanide
Organic polymers
Physicochemistry of polymers
Polymers
prebiotics
Properties and characterization
sodium
Sodium cyanide
Spectrometers
temperature
thermal analysis
Thermal and thermodynamic properties
Thermal decomposition
thermal degradation
thermal properties
thermogravimetry
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Summary:This paper presents a thermogravimetry (TG) study of hydrogen cyanide polymers, synthesized from the reaction of equimolar aqueous solutions of sodium cyanide and ammonium chloride. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were also used to evaluate the thermal behaviour of these black polymers, which play an important role in prebiotic chemistry. A coupled TG–mass spectrometer (MS) system allowed us to analyze the principal volatile thermal decomposition and fragmentation products of the isolated HCN polymers under dynamic conditions and an inert atmosphere. After dehydration, a multi-step decomposition occurred in this particular polymeric system, due to the release of ammonia, hydrogen cyanide (depolymerization reaction), isocyanic acid (or cyanic acid) and formamide; these two latter species allow us identify bond connectivities. Finally, data collected from TG experiments in an oxidative atmosphere showed significant differences at higher temperatures, above 400 °C. According to these results, the different techniques of thermal analysis here applied have demonstrated to be an adequate methodology for the study and characterization of this complex macromolecular system, whose structure remains controversial even today.
ISSN:0141-3910
1873-2321
DOI:10.1016/j.polymdegradstab.2011.01.033