Call us toll-free

Synthesis and post-polymerization modification of …

Expanding the Diversity of Chemical Protein Modification Allows Post-Translational Mimicry.

Approximate price

Pages:

275 Words

$19,50

Post-polymerization modification of poly(L-glutamic …

Abstract:
The present study evaluates the mechanical performance of a Hot Mix Asphalt – Type II (HMA-2) modified with carbon nanotubes and carbon nanofibers (CNTF). CNTF were made by means the Catalytic Vapor Deposition (CVD) technique at 700° C using a Nickel, Copper and Aluminum (NiCuAl) catalyst with a Cu/Ni molar relation of 0,33. In order to properly assess HMA-2 performance, three different mixtures were analyzed: 1) HMA-2 modified with purified CNTF; 2) HMA-2 modified with non-purified CNTF and, 3) a Conventional HMA-2 (control). Samples manufactured in accordance with the Marshall Mix Design were tested in the laboratory to study rutting, resilient modulus (Mr) and fatigue. In addition to the aforementioned dynamic characterization, the effect of CNTF purification on the asphalt mixture’s mechanical properties was analyzed. In short, a comparative study was designed to determine whether or not CNTF should be purified before introduction into the HMA-2. This investigation responds to the growing demand for economical materials capable of withstanding traffic loads while simultaneously enhancing pavement durability and mechanical properties. Although purified CNTF increased HMA-2 stiffness and elastic modulus, non-purified CNTF increased the asphalt mixture’s elastic modulus without considerable increases in stiffness. Thus, the latter modification is deemed to help address fatigue related issues and improve the long-term durability of flexible pavements.

Post-polymerization modification of poly(vinyl ether)s: …

Abstract:
In this work, we present functionalization of AISI 316L surfaces by nanosecond Nd:YAG laser texturing and adsorption of superhydrophobic fluoroalkylsilane functionalized nano SiO2 particles. Surface modification by tuning the distance between laser-produced micro(μ)-channels lead to different surface roughness. After nanosilica coatings the superhydrophilic laser-textured surfaces are turned into superhydrophobic surfaces with the same μ-roughness. The higher μ-channels density leads to more hydrophobic surfaces after coating. This enable a study of combined effect of surface wettability and morphology on friction coefficient and wear resistance. The experiments were performed in air and water environment. In case of dry friction, increased μ-roughness lead to higher friction coefficient and the water-repellency modification by nanosilica particles has no influence on tribological behavior. On the contrary, in water environment the wettability presents important contribution to the properties of contact surfaces - hydrophobic surfaces express lower friction coefficient, especially at higher densities of μ-channels. The EDS analysis of worn and unworn surfaces is performed indicating the difference in Si wt% in air and water environment connected to the difference in coefficient of friction.

"In situ quenching and post-polymerization modification …

Functional polymers by post-polymerization modification : concepts, guidelines, and applications

This mini-review provides an introduction to the key work in the area of synthesis and post-polymerization functionalization of maleimide-functional polymers. The versatility and utility of the maleimide group in the efficient functionalization of polymers by both 'thiol-ene' Michael addition and Diels-Alder cycloaddition chemistries are highlighted.

The synthesis of vinyl bromobutanoate (VBr), a new vinyl acetate monomer derivative obtained by the palladium-catalyzed vinyl exchange reaction between vinyl acetate (VAc) and 4-bromobutyric acid is reported. The homopolymerization of this new monomer using the RAFT/MADIX polymerization technique leads to the formation of novel well-defined and controlled polymers containing pendent bromine functional groups able to be modified via postpolymerization modification. Furthermore, the copolymerization of vinyl bromobutanoate with 2-methylene-1,3-dioxepane (MDO) was also performed to deliver a range of novel functional degradable copolymers, poly(MDO--VBr). The copolymer composition was shown to be able to be tuned to vary the amount of ester repeat units in the polymer backbone, and hence determine the degradability, while maintaining a control of the final copolymers’ molar masses. The addition of functionalities via simple postpolymerization modifications such as azidation and the 1,3-dipolar cycloaddition of a PEG alkyne to an azide is also reported and proven by 1H NMR spectroscopy, FTIR spectroscopy, and SEC analyses. These studies enable the formation of a novel class of hydrophilic functional degradable copolymers using versatile radical polymerization methods.

Click Chemistry Publications - Scripps Research Institute

This mini-review provides an introduction to the key work in the area of synthesis and post-polymerization functionalization of maleimide-functional polymers. The versatility and utility of the maleimide group in the efficient functionalization of polymers by both 'thiol-ene' Michael addition and Diels-Alder cycloaddition chemistries are highlighted.

Thus, diverse libraries of functional polymers with identical average degrees of polymerization but variable side chain functionality may easily be generated.

Filling the gap for a book dealing with synthetic strategies and recent developments, this volume provides a comprehensive and up-to-date overview of the field of post-polymerization modification.

Order now
  • PDF Downloads : Oriental Journal of Chemistry

    The synthesis of functional polymers has been enriched dramatically by post-polymerization modifications

  • Post-Polymerization Modification | Request PDF

    06/11/2016 · Copolymer Synthesis and Characterization by Post-Polymerization Modification: ..

  • 12/01/2018 · Hall, Daniel J., Van Den Berghe, Helene M

    937: Zhang, Y.-H.; Gao, Z.-X.; Zhong, C.-L.; Zhou, H.-B.; Chen, L.; Wu, W.-M.; Peng, X.-J.; Yao, Z.-J

Order now

Functional Degradable Polymers by Radical Ring …

Biography:
Mrs Shaista Taimur is a PhD scholar from Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan. Her PhD degree is in Materials Engineering (2017). She is scientifically skilled in polymeric nanohybrid composites synthesis and processing. Her reserach area and expertise are clay polymer nanocomposites (CPNs) synthesis and processing with special focus on chemical and radiation grafting, Organic-inorganic nanohybrids and their applications in toxic and precious metals removal and recovery and modification of nanoclay (sepiolite) for tailor made properties and applications. She has three international publications. She has teaching experience in different institutions of Pakistan.

Post-Polymerization Modification - Surrey Research …

Biography:
Mrs Shaista Taimur is a PhD scholar from Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan. Her PhD degree is in Materials Engineering (2017). She is scientifically skilled in polymeric nanohybrid composites synthesis and processing. Her reserach area and expertise are clay polymer nanocomposites (CPNs) synthesis and processing with special focus on chemical and radiation grafting, Organic-inorganic nanohybrids and their applications in toxic and precious metals removal and recovery and modification of nanoclay (sepiolite) for tailor made properties and applications. She has three international publications. She has teaching experience in different institutions of Pakistan.

Click Chemistry -- Publications - The Scripps Research …

Abstract:
Inorganic fertilizers along with high yielding varieties have contributed immensely for success of green revolution. Increasing pressure towards food production globally demands unconscientious fertilizer usage in future as well. Nitrogenous fertilizers are the extensively used fertilizers but also suffer huge losses from agriculture ecosystem due to faster rate of release which is not synchronized with crop demand. Thus resulting in low nitrogen use efficiency. In order to have a sustained release of nitrogen from fertilizer, nanoparticle coated with urea is an effective option. We report urea coated hydroxyapatite based nanofertilizer and its performance on aerobic paddy. In this study hydroxyapatite (HA) nanoparticles were synthesized by adding orthophosphoric acid to calcium hydroxide solution under constant vigorous stirring. Saturated urea solution was added to the HA particle suspension and was stirred continuously for 12 hours for surface modification. The urea modified HA particles were washed and dried at 65ºC. Hydroxyapatite nanoparticles (HA) and urea coated hydroxyapatite nanoparticles (UHA) were characterized using Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), Powder X-ray Diffraction (PXRD) and Fourier Transform Infrared (FTIR) Spectroscopy. Nitrogen content of UHA was analyzed using Kjeldahl method. Nitrogen content of UHA particles was found to be 36% and Zeta potential was 165.0 mV indicating stable nanodispersion. PXRD pattern of UHA particles indicated the presence of peaks due to hydroxyapatite and urea. SEM images of UHA particles exhibited oblong structures resembling rice grains with diameter less than 90 nm. FTIR spectroscopy showed prominent peaks around γmax/cm–1 1041 indicating phosphate group in hydroxyapatite and γmax/cm–1 3336 and 3432 indicating presence of urea. Synthesized nanofertilizer was evaluated on aerobic paddy under completely randomized design and was compared with recommended dose of conventional urea (100kgN/ha) in aerobic paddy. Nanofertilizer at 25% of recommended dose recorded highest grain yield. Nanofertilizer@ 50% dose showed similar performace to 100% dose of conventional urea. The results indicate amount of fertilizer application into soil can be reduced than regular dosage with nanofertilizer without affecting the yield. This will reduce environmental pollution of water and soil without compromising agricultural production.

Order now
  • Kim

    "I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."

  • Paul

    "Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."

  • Ellen

    "Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."

  • Joyce

    "Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."

  • Albert

    "Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."

  • Mary

    "Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."

Ready to tackle your homework?

Place an order