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You searched for subject:(hairy particles). Showing records 1 – 2 of 2 total matches.

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University of Tennessee – Knoxville

1. Wright, Roger Anthony Emory. Synthesis and Application of Polymer Brush-Grafted Nanoparticles as Hydrogel Gelators and Lubricant Additives.

Degree: 2016, University of Tennessee – Knoxville

This dissertation describes the synthesis of polymer brush-grafted nanoparticles (hairy NPs) and an analysis of their behavior or utility in multiple areas. The hairy NPs were synthesized from silica NPs functionalized with initiating moieties by surface-initiated atom transfer radical polymerization. A brief introduction to hairy NPs, with a focus on the synthesis and behavior of stimuli-responsive polymer brush-grafted particles, is given in Chapter 1 to provide context for this work. Chapters 2 and 3 present the synthesis of thermosensitive diblock copolymer brush-grafted nanoparticles designed as hairy NP analogues in place of thermosensitive block copolymers micelles for the construction of hybrid, physical hydrogels. Chapter 2 details a series of hairy NPs with a thermosensitive poly(methoxydi(ethylene glycol) methacrylate) (PDEGMMA) inner block and a charge-bearing, poly(DEGMMA-co-2-(methacryloyloxy)ethyltrimethylammonium iodide) (PDEGMMA-co-TMAEMA-I) outer block. These hairy particles underwent a reversible, cooling-induced gelation at moderate concentrations in water, based on the packing of hairy NPs due to the LCST-driven increase in brush volume fraction upon cooling. Another series of thermosensitive hairy NPs was made with brushes composed of P(TMAEMA-I)-b-PDEGMMA, which exhibited a heating-induced reversible gelation at concentrations as low as 3 wt % in water, due to the association of PDEGMMA outer blocks at temperatures above their LCST. The inner hydrophilic polyelectrolyte block served to bridge these domains and NPs to form a three-dimensional gel network. Chapter 4 details the use of NPs grafted with oil-soluble poly(lauryl mathacrylate) as lubricant additives. These hairy NPs showed superior stability in a poly(alphaolefin) (PAO) base lubricating oil, and the addition of 1.0 wt % hairy NPs to PAO yielded significant reductions in both friction and material wear. These gains were attributed to the formation of a load-bearing tribofilm at the rubbing interface. Chapter 5 explores the brush microphase separation of poly(n-butyl acrylate)-b-polystyrene (PnBA-b-PS) brush-grafted particles with PnBA as inner block. From TEM analysis, there appeared an evolution of phase morphology from a stripe-like nanostructure to a more uniform layered structure with increasing PS molecular weight, in qualitative agreement with simulation studies. Chapter 6 includes a look back on this dissertation work in its entirety and possible future work.

Subjects/Keywords: hairy particles; physical hydrogels; stimuli-responsive polymers; Polymer Chemistry

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wright, R. A. E. (2016). Synthesis and Application of Polymer Brush-Grafted Nanoparticles as Hydrogel Gelators and Lubricant Additives. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/3982

Chicago Manual of Style (16th Edition):

Wright, Roger Anthony Emory. “Synthesis and Application of Polymer Brush-Grafted Nanoparticles as Hydrogel Gelators and Lubricant Additives.” 2016. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed December 12, 2019. https://trace.tennessee.edu/utk_graddiss/3982.

MLA Handbook (7th Edition):

Wright, Roger Anthony Emory. “Synthesis and Application of Polymer Brush-Grafted Nanoparticles as Hydrogel Gelators and Lubricant Additives.” 2016. Web. 12 Dec 2019.

Vancouver:

Wright RAE. Synthesis and Application of Polymer Brush-Grafted Nanoparticles as Hydrogel Gelators and Lubricant Additives. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2016. [cited 2019 Dec 12]. Available from: https://trace.tennessee.edu/utk_graddiss/3982.

Council of Science Editors:

Wright RAE. Synthesis and Application of Polymer Brush-Grafted Nanoparticles as Hydrogel Gelators and Lubricant Additives. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2016. Available from: https://trace.tennessee.edu/utk_graddiss/3982

2. Jiang, Xiaoming. Hairy Particles: Polymer Brush-Supported Organocatalysts and Asymmetric Mixed Homopolymer Brushes.

Degree: 2010, University of Tennessee – Knoxville

This dissertation presents the synthesis and studies of polymer brush-supported organocatalysts and asymmetric mixed homopolymer brushes grafted on particles. The brushes were synthesized from initiator-functionalized particles by surface-initiated “living” radical polymerizations. Polymer brush-supported organocatalysts were designed to combine the advantages of both soluble polymer- (high activity) and crosslinked insoluble polymer-supported catalysts (recyclability). Chapter 1 describes the synthesis of a polymer brush-supported 4-N,N-dialkylaminopyridine (DAAP) catalyst from initiator-functionalized latex particles by surface-initiated nitroxide-mediated radical polymerization (NMRP). The hairy particles efficiently catalyzed the acylation of secondary alcohols and Baylis-Hillman reaction and were recycled  six times with no or negligible decrease in the reaction yield. Chapter 2 presents the synthesis of a thermosensitive polymer brush-supported DAAP by surface-initiated atom transfer radical polymerization (ATRP) from silica particles with addition of a free initiator. Both hairy particles and the free copolymer formed from the free initiator were used as catalysts for hydrolysis of nitrophenyl acetate at various temperatures. Below the lower critical solution temperature (LCST), the activity of hairy particles was very close to that of the free copolymer. LCST transitions exerted different effects on the reactions catalyzed by hairy particles and the free copolymer. Chapters 3 and 4 present the studies of the effects of chain length disparity and grafting density on phase morphology of mixed brushes grafted on silica particles. A series of mixed poly(tert-butyl acrylate) (PtBA)/polystyrene (PS) brushes with a fixed PtBA molecular weight and various PS molecular weights were grown from silica particles functionalized with a monochlorosilane-terminated asymmetric difunctional initiator (Y-initiator) by sequential ATRP and NMRP. The total grafting densities of these brushes were 0.6 – 0.7 chains/nm2. The morphology of mixed brushes evolved from isolated PS nanodomains, to short PS cylinders, to a nearly bicontinuous nanostructure, and a two-layered nanostructure with the change of chain length disparity of two homopolymers. To study the grafting density effect, a set of high density asymmetric mixed brushes with total grafting densities of 0.9 – 1.2 chains/nm2 was prepared from triethoxysilane- terminated Y-initiator-functionalized silica particles. The feature sizes of the patterns formed from high density mixed brushes were much smaller than those of lower density mixed brushes.

Subjects/Keywords: Hairy Particles; Polymer Brush; Catalysis; Microphase Separation; Polymer Chemistry

…of Sterically Hindered Alcohols with Hairy Particles as Catalyst… …Hairy Particles and Free Copolymer at Temperatures below the LCST of Polymer Brushes… …17 Figure 1.3. Optical pictures of (a) a dispersion of hairy particles in the… …reaction mixture and (b) the hairy particles isolated by centrifugation… …mixture with hairy particles as catalyst after 24 h (catalyst loading: 17.4 mol %)… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Jiang, X. (2010). Hairy Particles: Polymer Brush-Supported Organocatalysts and Asymmetric Mixed Homopolymer Brushes. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/808

Chicago Manual of Style (16th Edition):

Jiang, Xiaoming. “Hairy Particles: Polymer Brush-Supported Organocatalysts and Asymmetric Mixed Homopolymer Brushes.” 2010. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed December 12, 2019. https://trace.tennessee.edu/utk_graddiss/808.

MLA Handbook (7th Edition):

Jiang, Xiaoming. “Hairy Particles: Polymer Brush-Supported Organocatalysts and Asymmetric Mixed Homopolymer Brushes.” 2010. Web. 12 Dec 2019.

Vancouver:

Jiang X. Hairy Particles: Polymer Brush-Supported Organocatalysts and Asymmetric Mixed Homopolymer Brushes. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2010. [cited 2019 Dec 12]. Available from: https://trace.tennessee.edu/utk_graddiss/808.

Council of Science Editors:

Jiang X. Hairy Particles: Polymer Brush-Supported Organocatalysts and Asymmetric Mixed Homopolymer Brushes. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2010. Available from: https://trace.tennessee.edu/utk_graddiss/808

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