Dissertation > Excellent graduate degree dissertation topics show

Surface Modification of Natural Polymer Materials via Surface-Initiated ATRP

Author: TangFan
Tutor: ChengZhenPing
School: Suzhou University
Course: Polymer Chemistry and Physics
Keywords: Atom transfer radical polymerization (ATRP) Activators generated by electron transfer (AGET) ATRP Surface modification Chitosan Filter paper
CLC: O631.3
Type: Master's thesis
Year: 2009
Downloads: 202
Quote: 2
Read: Download Dissertation

Abstract


In this thesis, surface modification of natural polymer materials via AGET ATRP (Atom Transfer Radical Polymerization with Activators Generated by Electron Transfer) or normal ATRP was demonstrated. The obtained materials composed of natural polymers and synthetic polymers have both advantages of natural polymers and synthetic polymers, which facilitates wider applications of the natural polymer materials.The work in this thesis can be summarized as follows:(1) Surface modification of chitosan nannospheres via iron-mediated AGET ATRP. Cross-linked chitosan nanospheres (SCTS) with an average diameter of 80 nm, were first prepared in a water/oil emulsion using glutaraldehyde as a crossing agent, and ATRP initiators were immobilized on the surfaces of the nanospheres. Iron(III)-mediated surface AGET ATRP was then successfully carried out on the SCTS using FeCl3ยท6H2O as the catalyst, PPh3 as the ligand, and ascorbic acid (VC) as the reducing agent in the presence of a limited amount air. The homopolymer, poly(methyl methacrylate) (PMMA), and amphiphilic block copolymer poly(methyl methacrylate)-b-poly(poly(ethylene glycol)methylether methacrylate) (PMMA-b- P(PEGMA)) were grafted onto the surfaces of the SCTS. Well-defined polymer chains were grown from the SCTS surfaces to yield individual nanospheres composed of a chitosan core and a well-defined, densely grafted outer PMMA or PMMA-b-P(PEGMA) layer. The kinetic of surface-initiated AGET ATRP of MMA in the presence of a limited amount of air was investigated. Linear kinetic plot and linear increase of molecular weight (Mn) with conversion for the sacrificial initiator initiated solution AGET ATRP, and linear plot of grafted percentage verse time were observed. The chemical composition of the nanosphere surfaces at different surface modification stages was validated by Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS).(2) Synthesis of filter paper with antibacterial activity via surface-initiated ATRP. Poly(tert-butyl acrylate) (PtBA) brushes were successfully grafted on the cellulose filter papers via surface-initiated ATRP. Then the grafting PtBA brushes were transferred into poly(acrylic acid) (PAA) in the presence of trifluoroactic acid (TFA), which can form chelate complexes with Ag+. The Ag+ was reduced in situ to obtain the silver nanoparticles modified cellulose filter papers. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA) and X-ray diffraction (XRD) were used to characterize the resulting products. The morphologies of the filter paper at different stages of surface modification were investigated by field emission scanning electron microscopy (FESEM). The silver nanoparticles modified filter paper performed good antibacterial ability against E. coli as compared with the original filter paper and PAA modified filter paper.

Related Dissertations

  1. Studies on Chitosan and Its Derivatives Adsorption for Paralytic Shellfish Poisoning in Ostrea Rivularis Could,TS254.4
  2. Thermal Stability of Complexes of Chitosan Quaternary Ammonium Salt and Metal Ion,O634
  3. Polyethylenimine Conjugated Stearic Acid-g-chitosan Oligosaccharide Micelles for Antitumor Gene Therapy,R450
  4. Preparation and Characterization of the OCS/PLLA Composite Film for Biomedical Materials,R318.08
  5. Study on the Accumulation and Remove of Cadmium and Lead in Oysters,X174
  6. Synthesis and Characterization of High-performance Polyacrylonitrile,O631.3
  7. Study on the Synthesis and Adsorption Behaviour of Chitosan Derivative,TS254.9
  8. Improvement of Preparation Technology for Chitin and Chitosan from By-product of Litopenaeus Vannamei,TS254.9
  9. Preparation of Crop Stalk-Based Sorption Materials with High Performances and Their Applications for Pah Removal from Water,X712
  10. Synthesis and Biocompatibility of different types of hydrophilic surface - modified polyurethane,R318.08
  11. Biological Control of Meloidogyne Spp. in Cucumber (Cucumis Sativus L.) and Development of the Ecological and Environment-friendly Fertilizer with Pesticides,S436.421
  12. Preparation and Properties of Chitosan-based Thermosensitive Composite Hydrogel,R943
  13. Acid solution on the structure and properties of chitosan / hydroxyapatite composite,R318.08
  14. Study on Chitosan-Based Composiate Nano-Coating Dope and Its Effect of Fresh-Keeping for Coated Egg,TS253.2
  15. Studies on the Dissolution of Chitosan in Ionic Liquids,O636.1
  16. Application Adipose-devired Stem Cells and Silk Fibroin and Chitosan Scaffold Materials Building Common Cells-stents Complex Experiments,R329
  17. Bovine serum albumin and protamine from NOCC / alginate hydrogels release : the isoelectric point of two different biological molecules controlled trial,R943
  18. Alginate - chitosan membrane in guided bone regeneration in applied research,R318.08
  19. Chitosan Supported Metal Complexes and Their Catalytic Oxidation Resistance,O634
  20. Polyaniline / short fiber reinforced natural rubber properties,TQ330.1
  21. Chitosan / tricalcium phosphate scaffold for tissue engineering Preparation and Properties,R318.08

CLC: > Mathematical sciences and chemical > Chemistry > Polymer chemistry ( polymer ) > Polymer physics and physical chemistry of polymers > The chemical nature of polymers
© 2012 www.DissertationTopic.Net  Mobile