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Hyperbranched Reaction Of Diene Monomers, And Synthesis And Application Of Aliphatic Tertiary Amine-based Hyperbranched Polymers

Posted on:2014-02-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:M SunFull Text:PDF
GTID:1221330398472877Subject:Polymer Chemistry and Physics
Abstract/Summary:PDF Full Text Request
Similar to the dendrimers, the hyperbranched polymers have low viscosity, high rheology, good solubility and a large number of functional groups, etc. However, their synthetic strategy is simple and low-cost, and the hyperbranched polymers have many potential applications. In-depth study on the synthetic strategy and polymerization mechanisms for preparation of new hyperbranched polymers has become an important research direction in the polymer fields. SCVP is a widely used synthetic method for the preparation of hyperbranched polymers, but its polymerization process, such as the structure of inimer at the initial stage has not been studied well. Through studying the structure of oligomers at the initial stage and the consumption rate of inimers, we can better understand how to prevent the cross-linking reaction, and how to increase the yields and molecular weights of the hyperbranched polymers.Another subject is the fluorescent labeling technology, which has become the most widely used marker technology because of its low cost, simple operation, clinical safety and high sensitivity. The preparation of excellent performance substance is very important for the fluorescent labeling technique. Looking for new biocompatible fluorescent materials has been the hot topic. Recently, a kind of non-traditional chromophore fluorescent polymer has attracted much attention. The study was mainly concentrated in the dendritic or hyperbranched PAMAMs. This kind of materials has good biocompatibility and fluorescence characteristics, and the study showed that the fluorescence of polymer came from the tertiary amine structure. But the study on the synthesis of tertiary amine-based hyperbranched polymers and their fluorescence properties has not been reported.In this dissertation, we mainly studied the synthesis and characterization of hyperbranched polymers, and their applications in the field of fluorescence techniques. Some achievements are as follows:1. During the ATRCP of MMA and DVB, we obtained a series of inimer oligomers and hyperbranched polymers formed via SCVP reaction. Increaseing the feed ratio of DVB to the initiator, and branched monomer reactivity, can increase the quantity of branching oligomer. Reaction between linear oligomers and AnB*can produce dimers, trimers, etc, and the hyperbranched polymers. The molecular weight distribution becomes broad with the progress of polymerization, while increasing the feed ratio of DVB can also broaden the molecular weight distribution. Gel can’t be produced by polymerization of the oligomer AB*and AnB*(n>2). Choosing ATRP initiating group with low activity, reducing the feed ratio of branched monomer, or reducing the ratio of branched monomers to initiators to less than1, can delay or even avoid the gel occurrence.2. We successfully synthesized the hyperbranched poly(ester-amine)s through the Michael addition polymerization of TMEA (B3) and the diacrylate (A2). With the proper feed molar ratio of the monomers, crosslinking reaction can be avoided, and the polymerization is easily controlled. The phenomena are similar to the polymerization of AB2monomers. At the initial stage of polymerization, the molecular weights increase slowly because the reactions occur between monomers, or oligomers, or oligomers and monomers, sharp increase of the molecular weights is observed at last stage of polymerization due to the reactions between the large molecules. The degree of branching had a slight increase with increase of the molecular weight. With increase of the linear chain length between the branch points, the fluorescence intensity and the fluorescence quantum yields of the polymers are significantly reduced.3. We successfully synthesized hyperbranched poly(ester amine) via the Michael addition polymerization of an acyclic tertiary amine, TMEA (B3) and the diacrylate (A2). The hyperbranched polymers with TMEA as branching units can retain high-efficient fluorescence of the acyclic tertiary amines. The linear polymers containing the tertiary amine in the main chain and side chains display low fluorescence. The fluorescence efficiency of the hyperbranched poly(ester amine)s increases with increase of their molecular weight. The aliphatic tertiary amine in the hyperbranched polymer is easily oxidized. After the oxidation, the absorption band of UV at320nm appears, and the fluorescence intensity at around410nm is reduced, but the fluorescence intensity at560nm increases.1H NMR and IR spectra indicate that the generation of Nâ†'O. Galactose-modified hyperbranched polymer HypET-AlpGP has good water solubility, low toxicity, and can well used in cell imaging. This kind of hyperbranched polymer with tertiary amine as branching units has a good prospect of application in the biological fields. 4. We successfully synthesized hyperbranched poly(ester amine) via the Michael addition polymerization of a cyclic tertiary amine, TMEMA (B3) and the diacrylat (A2). There are two key points for maintaining high fluorescence efficiency of the cyclic aliphatic tertiary amine groups. Firstly, the fluorescence efficiency increases gradually from0.12to0.49with the molecular weight increase of the HypTE; Secondly, the hyperbranched poly(ester amine)s having the cyclic tertiary amine as branching units display high fluorescence efficiency, and the fluorescence efficiency would be reduced when the tertiary amine groups are in the side chains of the hyperbranched polymers. Besides, the linear polymers with the tertiary amine groups at the main or side chains display low fluorescence efficiency. The fluorescence spectra of the cyclic aliphatic tertiary amine-based HypETs and the acyclic aliphatic tertiary amine-based HypTEs are similar in shape and position, but the HypETs have slightly higher fluorescence quantum yields compared to the HypTEs, while their molecular weights are similar. The galactose-modified HypTEs give bright images of cell and have very low cytotoxicity, and can be used in the field of cell imaging and drug derivery.5. We successfully synthesized a kind of water-soluble hyperbranched polyesters, HMBAPs containing cyclic aliphatic tertiary amine groups and a large number of hydroxyl groups on their surface through the polycondensation of the AB2monomer, MBAP, catalyzed by tetrabutyl titanate, and their fluorescence properties were investigated. The aliphatic tertiary amine fixed in the hyperbranched polymers can retain high-efficiency of the fluorescence. The tertiary amine-based linear polymer has weak fluorescence, and the hyperbranced polymers without the aliphatic tertiary amine, whose structure is similar to HMBAPs, didn’t exhibt the fluorescence. The fluorescence efficiency of the hyperbranched polymers increases with increase of the molecular weight. The results indicate that the branched structure is an important factor for retaining high fluorescence efficiency of the tertiary amine. Further more, when the cupric chloride was added into the aqueous solution of HMBAPs, the fluorescence was quenched significantly, indicating that the tertiary amine is responsible for the fluorescence. This type of polymer has a good fluorescence properties and a great application prospect.
Keywords/Search Tags:fluorescence, aliphatic tertiary amine groups, biology, Michael additionpolymerization, hyperbranched polymer, self-condensing vinylpolymerization
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