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Benicewicz和Tang教授学术报告(07-19)

( 2011-07-18 )

  7月19日上午9:30,在理化大楼一楼科技展厅,University of South Carolina的Benicewicz和Tang教授做学术报告。

  Gum Rosin-Derived Renewable Polymers: from Biodegradable Polymers to Antimicrobial Materials

  

  Chuanbing Tang

Department of Chemistry and Biochemistry & USC NanoCenter, University of South Carolina, Columbia, SC 29208 USA tang.c@chem.sc.edu

  

  In the field of natural biomass-derived renewable and sustainable polymers, a largely missing part from current efforts is to develop polymers with rich cycloaliphatic and/or aromatic structures resembling one of the core chemistries of hydrocarbon-based petroleum chemicals. We target on Gum Rosin, an exudate obtained from living pine trees and other plants. The major components of rosin are resin acids with characteristic hydrocarbon-based hydrophenanthrene rings, which provide hydrophobicity and bulkiness suitable for many applications. We have functionalized carboxylic acids and conjugated dienes of resin acids to achieve desirable chemical architectures and properties via controlled polymerization and highly efficient click chemistry. This presentation will cover the following topics: 1) synthesis and polymerization of new monomers; 2) biodegradable polyesters; 3) antimicrobial polymers.

  Functionalization of Silica Nanoparticles by Surface-Initiated RAFT Polymerization

  

  Brian C. Benicewicz

 Department of Chemistry and Biochemistry & USC NanoCenter, University of South Carolina, Columbia, SC 29208 USA benice@sc.edu

  

  Reversible addition-fragmentation chain transfer (RAFT) polymerization has been applied to the controlled polymerization of various monomers under a broad range of conditions to prepare polymer materials with predetermined molecular weights, low polydispersities, and advanced architectures. The combination of the RAFT technique with polymer grafting techniques has been widely used as an approach to modify the surfaces of nanoparticles with a variety of functional polymers. In our work, we have developed multiple approaches for attaching RAFT agents to the surface of nanoparticles. Using these surface-immobilized RAFT agents, styrenic, acrylate, and methacrylate monomers could be polymerized on the nanoparticle surfaces via surface-initiated RAFT polymerization in a controlled manner. The availability of the wide range of graft densities allowed us to study the polymer chain behavior in both the brush and mushroom regions. We have also utilized click chemistry techniques to modify the surface of nanoparticles. Graft polymerization of azido-containing monomers was accomplished from the silica nanoparticle surfaces via surface-initiated RAFT polymerization under mild conditions. The resulting polymer-grafted nanoparticles contain a large number of reactive azido groups, which can subsequently click functionalized with different groups for polymer nanocomposite applications. This synthetic strategy is also applicable to the growing library of monomers from renewable natural resources.


 
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