Poly(propylene imine) dendrimers as hydrogen donor in Type II photoinitiated free radical polymerization

Three generations of poly(propylene imine) dendrimers, namely (PPI-16, PPI-32 and PPI-64; 16, 32 and 64 for generations 3, 4 and 5, respectively) were used as hydrogen donors in photoinitiated free radical polymerization of methyl methacrylate by using one of the following photosensitizers; benzophe...

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Bibliographic Details
Published in:European polymer journal 2007-10, Vol.43 (10), p.4423-4430
Main Authors: Tasdelen, M. Atilla, Demirel, A. Levent, Yagci, Yusuf
Format: Article
Language:English
Subjects:
Applied sciences
Dendrimer-star polymers
Exact sciences and technology
Free radical polymerization
Methyl methacrylate
Photopolymerization
Physicochemistry of polymers
Poly(propylene imine) dendrimers
Polymerization
Polymers and radiations
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Summary:Three generations of poly(propylene imine) dendrimers, namely (PPI-16, PPI-32 and PPI-64; 16, 32 and 64 for generations 3, 4 and 5, respectively) were used as hydrogen donors in photoinitiated free radical polymerization of methyl methacrylate by using one of the following photosensitizers; benzophenone and thioxanthone. The effect of generation number of the dendrimer on photoinitiation efficiency and molecular weight of the resulting polymers was investigated. Glass transition temperatures and particle size measurements of the resulting polymers indicated the presence of nearly stretched polymer chains around the dendrimers. The location of hydrogen donating sites was evaluated by photolysis studies in the absence of monomer by using a stable radical namely, 2,2,6,6-tetramethylpiperidine- N-oxyl free radical (TEMPO) and showed that hydrogen abstraction occurs from the inner tertiary amino groups. The TEMPO attached dendrimers were further used in the nitroxide mediated radical polymerization (NMP) of styrene to yield star polymers.
ISSN:0014-3057
1873-1945
DOI:10.1016/j.eurpolymj.2007.05.042