Cationic photopolymerization of 3‐benzyloxymethyl‐3‐ethyl‐oxetane

Abstract

The cationic photopolymerization of 3-benzyloxymethyl-3-ethyl-oxetane (MOX104) initiated by triphenylsulfonium hexafluoroantimonate under UV light was conducted. The kinetics were investigated by real-time Fourier transform IR spectroscopy and the mechanical and thermal properties of poly(MOX104) were examined by dynamic mechanical analysis and TGA. To adjust the properties of the polymer, different initiator concentrations and comonomer composition were applied. The results showed that the conversion of MOX104 was improved significantly from 17% to almost 90% by adding a certain amount of 3,4-epoxycyclohexane carboxylate or diglycidyl ether of bisphenol A epoxy resin, while not much effect was observed by adding 1,4-butanediol diglycidyl ether. Moreover, the glass transition temperature, decomposition temperature and Young's modulus of poly(MOX104) were improved by adding different amounts of diglycidyl ether of bisphenol A epoxy resin.

NIR‐Sensitized Cationic and Hybrid Radical/Cationic Polymerization and Crosslinking

“…Since this temperature appeared quite high, it was dispensed to continue the experiment at temperatures >250 °C because data obtained would not reliably describe mechanical relaxation of this system due to possible thermal damage. Nevertheless, our experiments confirm findings obtained by UV exposure that curing of oxetanes results in tanδ curves showing more than one peak [52, 53, 68] …”

“…Since this temperature appeared quite high, it was dispensed to continue the experiment at temperatures > 250 8 8Cb ecause data obtained would not reliably describe mechanical relaxation of this system due to possible thermal damage.N evertheless,o ur experiments confirm findings obtained by UV exposure that curing of oxetanes results in tand curves showing more than one peak. [52,53,68] Conclusion NIR-sensitized photopolymerization comprising as ensitizer with bridged pattern to avoid bond cleavage of the polymethine chain, and therefore formation of nucleophilic products in combination with an iodonium salt, showed good performance upon exposure to ah igh-intensity NIR LED emitting at 805 nm;t hat is in general as tructural pattern comprising either an indolium or benzo[e]indolium pattern. Furthermore,ananion with optimal shielding of nucleophilic moieties of the anion and large anion radius showed the best performance as observed by real-time FTIR spectroscopy.…”

NIR‐sensibilisierte kationische und hybride radikalische/kationische Polymerisation und Vernetzung

“…Da diese Temperatur ziemlich hoch erschien, wurde darauf verzichtet, das Experiment bei Temperaturen >250 °C fortzusetzen, da solche Daten die mechanische Relaxation dieses Systems aufgrund einiger möglicher thermischer Schäden nicht zuverlässig beschreiben würden. Unsere Experimente bestätigen jedoch die durch UV‐Bestrahlung erhaltenen Ergebnisse, dass die Aushärtung von Oxetanen zu tanδ‐Kurven führt, die mehr als einen Peak zeigen [52, 53, 68] …”

“…Da diese Temperatur ziemlich hoch erschien, wurde darauf verzichtet, das Experiment bei Te mperaturen > 250 8 8Cf ortzusetzen, da solche Daten die mechanische Relaxation dieses Systems aufgrund einiger mçglicher thermischer Schäden nicht zuverlässig beschreiben würden. Unsere Experimente bestätigen jedoch die durch UV-Bestrahlung erhaltenen Ergebnisse,d ass die Aushärtung von Oxetanen zu tand-Kurven führt, die mehr als einen Peak zeigen [52,53,68]. Schlussfolgerungen Die NIR-sensibilisierte Photopolymerisation mit einem Sensibilisator,d er ein verbrücktes Substitutionsmuster in zentraler Position besitzt, um eine Bindungsspaltung der Polymethinkette und damit die Bildung nukleophiler Produkte zu vermeiden, erfolgt in Kombination mit einem Iodoniumsalz mit guter Effektivitätbei Bestrahlung mit einer NIR-LED,d ie mit hoher Intensitätb ei 805 nm emittiert.…”

Density functional theoretical studies on the ring-opening polymerization mechanism of oxetane cation series compounds

“…The most important uses of oxetane and its derivatives are in the eld of cationic photo-polymerization, [25][26][27][28][29] since oxetane is the simplest molecule in the series of oxygen hetero-ring compounds. Understanding the single molecular polymerization mechanism of oxetane is very signicant for explaining the more complex polymerization mechanisms of oxetane derivatives.…”