Thermolysis of poly(diaryl diazosulfide)s

Abstract

Dedicated to Prof. Dr. R. Kerber on the occasion of his 70th birthday SUMMARY:Poly(diary1 diazosu1fide)s and model diary1 diazosulfides of the general structure aryl-N = N-S-aryl' are tested for their thermostability. Thermolysis in solution is followed by means of UV spectroscopy. At the beginning of the decay most model diazosulfides follow first-order kinetics, but show an acceleration of the decay rate in the further course of the thermolysis. In contrast to the models the decomposition of the corresponding polymers cannot be described by first-order kinetics, except one example (P 1).Thermogravimetry studies show weight losses of 8 -12% in the range between 80 and 150 "C depending on the structure of the models and polymeric diazosulfides. These values correspond with the content of azo function in these compounds, therefore it is assumed that nitrogen is split off under these reaction conditions. ZUSAMMENFASSUNG:Die Thermostabilitat von Poly(diary1 diazosu1fid)en und Diaryldiazosulfid-Modellsubstanzen mit der allgemeinen Struktur Aryl-N=N-S-Aryl' wird untersucht. Die Thermolyse in Ldsung wird mit UV-Spektroskopie verfolgt. Die meisten Modell-Diazosulfide folgen zu Beginn des Abbaus einer Kinetik erster Ordnung, zeigen aber im weiteren Verlauf der Thermolyse eine Beschleunigung der Abbaugeschwindigkeit. Im Gegensatz dazu kann die Zersetzung der entsprechenden Polymeren (aul3er im Fall von P 1) nicht durch ein Geschwindigkeitsgesetz erster Ordnung beschrieben werden. Thermogravimetrische Untersuchungen zeigen im Temperaturbereich von 80 bis 150 "C Gewichtsverluste zwischen 8 und 12'70, abhhgig von der Struktur der Diazosulfid-Modellsubstanzen bzw. -Polymeren. Die Werte entsprechen den Gehalten an Azo-Gruppen der Verbindungen, so da8 angenommen wird, da8 unter diesen Reaktionsbedingungen Stickstoff abgespalten wird.

Isomerization and decomposition of a poly(alkylaryldiazosulfide): Comparison of thermolytically and photolytically induced reactions

“…The average of the values determined as being the activation energy of compound I in substance is approximately 152 kJ mol -1 . This is somewhat higher compared to the decomposition activation energy of 140 kJ mol -1 reported for a poly(diaryldiazosulfide) compound in DMAc 18) .…”

“…Diazosulfide compounds are known since 1884, when Stadler first synthesized instable alkylaryldiazosulfides from diazonium salts and ethylthiol 14) ; this achievement was followed by the synthesis of diaryldiazosulfides [15][16][17] . Diazosulfide groups exhibit a high photosensitivity and should therefore be interesting materials for microstructuring as well as for photo-and thermolabile microencapsulation 18) . Upon heating or irradiation with UV light, diazosulfides as well as other labile azo compounds release nitrogen 19) .…”

Poly(arylazophosphonate)s: A New Polymer Class with Arylazophosphonate Units in the Main Chain

“…2,3 Besides poly(pentazadiene)s 4 and poly(hexazadiene)s, 5 which have been prepared and intensely investigated, heteroatom-containing azopolymers, such as poly(diaryldiazosulfide)s, also showed promising photo-and thermosensitive properties. 6,7 A new class of polymers with azo-derived functional groups are poly(arylazophosphonate)s. Arylazophosphonates ( 3) have been well-known for almost 40 years. The first synthesis was described in 1958 by F. Suckfu ¨ll and H. Haubrich.…”

“…In earlier works the successful application of the concept has already been demonstrated with poly(triazene)s containing three connected nitrogen atoms in the backbone. As a result of their high thermal stabilities combined with favorable photolytic sensitivities, triazene polymers are suitable materials for laser-induced microimaging. , Besides poly(pentazadiene)s and poly(hexazadiene)s, which have been prepared and intensely investigated, heteroatom-containing azopolymers, such as poly(diaryldiazosulfide)s, also showed promising photo- and thermosensitive properties. , …”