4-[Diphenyl(trimethylsilyl)methyl]benzophenone as initiator in the photopolymerization of methyl methacrylate and styrene
Φόρτωση...
Ημερομηνία
Συγγραφείς
Tasis, D. A.
Siskos, M. G.
Zarkadis, A. K.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Wiley-VCH Verlag
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Macromolecular Chemistry and Physics
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
The polymerization of methyl methacrylate (MMA) and styrene (St) has been studied using 4-[diphenyl(trimethylsilyl)methyl]benzophenone 1 as photoinitiator. The polymerization follows a free radical mechanism; the polymerization rate increases linearly with the monomer concentration and was found to be proportional to the 0.33 and 1.40 power of the photoinitiator and the monomer (MMA) concentration, respectively. The overall activation energy in the case of MMA photopolymerization was calculated to be 25.0 kJ/mol. From H-1 NMR studies it is concluded that the obtained polymers contain two different trimethylsilyl moieties, one at the head and the other at the tail of the polymer chain, showing primary termination reactions even at low initiator concentrations. The p-benzoyltrityl radical 1(.) is incorporated into the polymer chain to a very small extent, acting as a scavenger. This is also concluded by laser flash photolysis (LFP) and ESR spectroscopy measurements. A. "living" character of the polymerization was observed only at very low initiator concentrations. The triplet state ((3)1*) of the initiator was quenched by styrene, reducing its efficiency. The rate constant k(q) of the quenching process of (3)1* was measured by LFP (k(q) = 3.1 . 10(9) M-1 . s(-1)). The triplet state and the photodissociation efficiency of the initiator is unaffected by MMA at various concentrations.
Περιγραφή
Λέξεις-κλειδιά
free-radical polymerization, evaluated rate coefficients, hindered free-radicals, photoinitiators, systems, kinetics
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000075869600030
http://onlinelibrary.wiley.com/store/10.1002/(SICI)1521-3935(19980901)199:9<1981::AID-MACP1981>3.0.CO;2-G/asset/1981_ftp.pdf?v=1&t=hmsucdyn&s=3be37a9500d4a7085a20eeff8624d25283a66ec6
http://onlinelibrary.wiley.com/store/10.1002/(SICI)1521-3935(19980901)199:9<1981::AID-MACP1981>3.0.CO;2-G/asset/1981_ftp.pdf?v=1&t=hmsucdyn&s=3be37a9500d4a7085a20eeff8624d25283a66ec6
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας