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Amphiphilic Polymeric Photoinitiators And The Application In Preparation Of Metal Nanoparticles

Posted on:2011-02-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y N WenFull Text:PDF
GTID:1101360305456830Subject:Polymer Chemistry and Physics
Abstract/Summary:PDF Full Text Request
Photopolymerization have been widely used in coatings, inks, photoresists, adhesives and electronic package materials because of its outstanding properties, such as fast-curing, high efficiency, non-solvent and reaction at room temperature. As one of the most important components of photo-curing systems, photoinitiator attracts more attention. Compared with low molecular weight photoinitiators, polymeric photoinitiators can avoid migration, toxicity and bad compatibility with cured system through the flexible structure design, which is a trend of photoinitiator. Incorporation of hydrogen-abstraction low molecular weight photoinitiator and coinitiator amine into the same polymeric chain is benefit to the hydrogen-abstraction reaction and improves the photoinition efficiency.This thesis focuses on the designing of amphiphilic polymeric photoinitiators through introducing hydrogen-abstraction low molecular weight photoinitiator and coinitiator amine into the same polymeric chain as well as its application in the preparation of metal nanoparticles using photochemical method. Polymeric Michler's ketone photoinitiator (PMKPR) was synthesized through open-ring addition reaction between low molecular weight Michler's ketone (MK) and resorcinol diglycidyl ether (RDE), which possesses similar UV-vis absorption with low-molecular-weight model compounds and can initiate the photopolymerization of 2,2-bis[4-(acryloxypolyethoxy)phenyl] propane (A-BPE-10).Polymeric Michler's ketone photoinitiators with different flexible chain (PMKPG and PMKPP) were synthesized by incorporating MK and polyethylene glycol diglycidyl ether (PEO) and poly(propylene glycol) diglycidyl ether (PPO) into the same polymeric chain, respectively. These polymeric photoinitiators possess the similar characteristic UV-vis absorption of PMKPR, and their photobleaching behavior is similar. The Tg of PMKPR, PMKPG and PMKPP is 58.1 oC, -24.9 oC and -12.5 oC, respectively. Compared with PMKR and PMKPP, PMPPG possesses higher photoinitiation efficiency in initiating the photopolymerization of phenoxy ethyleneglycol acrylate (AMP-10G) and A-BPE-10, while PMKPP shows better efficiency in initiating the photopolymerizaiton of trimethylopropane triacrylate (TMPTA).A series of amphiphilic polymeric Michler's ketone photoinitiators (APMKs) were synthesized by incorporating PEO short chain, MK, and coinitiator piperazine into the same polymeric chain, which possess good amphiphilic ability and become water-soluble when the molar ratio of [MK]/[PEO]/[piperazine] is 2:3:1. APMKs also exhibit the similar absorption to MK derivates. With increasing of PEO content, APMK shows better solubility both in polar and non-polar monomers as well as the photoinitiation efficiency. As for photopolymerization of water-soluble polyethylene glycol diacrylate (PEGDA), the final conversion is higher than 94%. Therefore, APMKs will be expected to find potential in many fields. Amphipathic hyperbranched polymeric thioxanthone (TX) photoinitiators (AHPTXs) were synthesized by introducing TX, and polyethylene glycol monoethylether glycidyl ether (E-PEO) into periphery of hyperbranched poly(ethylene imine) (HPEI). AHPTXs possess similar UV-vis absorption spectra to TX derivatives, and weaker ?uorescence emission in comparison to low-molecular weight analogues, which can be easily dispersed in many solvents and acrylate monomers as well as water. In comparison to low-molecular weight analogues photoinitiator systems, AHPTXs are very efficient in photopolymerization of acrylamide (AM), PEGDA and A-BPE-10.Nanophotoinitiator was synthesized by introducing TX and PEO into the silica nanoparticles through esterification, which also shows good solubility in many monomers, similar spectra and weaker fluorescence emission in comparison to low molecular weight analogue and also shows good efficiency in photoinitiating the polymerization of PEGDA and A-BPE-10. Amphiphilic silver nanoparticles were synthesized in aqueous solution in the presence of APMK under UV irradiation. With the increasing of irradiation time, particles become uniform and the average particle size is 20 nm, which possess good solubility in both polar and non-polar solvents, and the particles can further photoinitiate the polymerization of monomers. Amphiphilic and multi-responsive gold nanoparticles (AuNPs) were synthesized in the presence of APMK and poly(ether amine) containing thiol groups (gPEA-SH) under UV irradiation, which possess a multi-stimuli response to temperature and pH and can be dissolved in many solvents. The density of gPEA-SH on the surface of AuNPs is about 0.2 chains/nm2 from the result of TGA. Phase transition appears upon changing the temperature or pH value. This kind of AuNP will have potential in biosensors and drug delivery.
Keywords/Search Tags:polymeric photoinitiator, amphipathy, Michler's ketone, thioxanthone, silver nanoparticles, gold nanoparticles
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