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Development of novel microencapsulat...

Yin, Weisi.

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Development of novel microencapsulation processes.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Development of novel microencapsulation processes./
Author:	Yin, Weisi.
Description:	118 p.
Notes:	Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 6413.
Contained By:	Dissertation Abstracts International70-10B.
Subject:	Chemistry, Polymer. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3381740
ISBN:	9781109425420

Development of novel microencapsulation processes.
Yin, Weisi.

Development of novel microencapsulation processes. - 118 p.

Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 6413.

Thesis (Ph.D.)--University of Rochester, 2009.

This thesis is for encapsulating additives into polymer particles using different techniques including emulsification/solvent evaporation, compressed carbon dioxide based microencapsulation, and encapsulation with porous polymer particles. Such microencapsulations can be applied to a vast range of areas, for example bio-labeling, controlled release, drug delivery, and printing.

ISBN: 9781109425420Subjects--Topical Terms:

1018428
Chemistry, Polymer.

Development of novel microencapsulation processes.
LDR:04610nam 2200337 4500 001 1391164
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008 130515s2009 ||||||||||||||||| ||eng d
020 $a 9781109425420
035 $a (UMI)AAI3381740
035 $a AAI3381740
040 $a UMI $c UMI
100 1 $a Yin, Weisi. $3 1669556
245 1 0 $a Development of novel microencapsulation processes.
300 $a 118 p.
500 $a Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 6413.
500 $a Adviser: Matthew Z. Yates.
502 $a Thesis (Ph.D.)--University of Rochester, 2009.
520 $a This thesis is for encapsulating additives into polymer particles using different techniques including emulsification/solvent evaporation, compressed carbon dioxide based microencapsulation, and encapsulation with porous polymer particles. Such microencapsulations can be applied to a vast range of areas, for example bio-labeling, controlled release, drug delivery, and printing.
520 $a Fluorescent CdSe/ZnS quantum dots (QDs) were incorporated into polyisoprene (PI) particles by emulsification/solvent evaporation. The simple method results in QDs encapsulated into the particle core without requiring chemical modification of the QDs. The fluorescence spectra of mixtures of two different-sized QDs change in PI as compared to their solution spectra, suggesting energy transfer between QDs due to their aggregation during the encapsulation. However, different emission peaks were clearly resolved, indicating that the particles are suitable for multicolor coding. The polyisoprene is easily cross-linked, and the cross-linking was shown to greatly enhance the fluorescence stability of the encapsulated QDs.
520 $a Ionic dyes were successfully encapsulated in polystyrene (PS) particles by CO2-based microencapsulation. The water-soluble dyes were made hydrophobic by forming ion pairs with alkyl quaternary ammonium cations. The hydrophobic ion pairs were then encapsulated in preexisting size monodisperse PS particles dispersed in water. High-pressure carbon dioxide swelled and plasticized PS and thus facilitated mass transport of the dye into the particles. The results show that the particles maintain their size and morphology after exposure to CO2, and that ion-paired dyes have significantly higher loading in the polymer particles than the original dyes. Addition of water-miscible cosolvents was shown to further enhance the incorporation of the hydrophobic ion pairs into the polymer colloids.
520 $a To encapsulate water-soluble additives, porous polymer particles were made by freeze-drying droplets of polymer solution suspended in water or from a spray. Hollow PS particles were obtained by swelling PS latex with solvent, freezing in liquid nitrogen, and drying in vacuum. It is shown that the particle morphology is due to phase separation in the polymer emulsion droplets upon freezing in liquid nitrogen, and that morphological changes are driven largely by lowering interfacial free energy. The dried hollow particles were resuspended in a dispersing media and exposed to a plasticizer, which imparts mobility to polymer chains, to close the surface opening and form microcapsules surrounding an aqueous core. The interfacial free energy difference between the hydrophobic inside and hydrophilic outside surfaces is the major driving force for closing the hole on the surface.
520 $a A controlled release biodegradable vehicle for drug was made by encapsulating procaine hydrochloride, a water-soluble drug, into the core of poly(DL-lactide) (PLA) microcapsules, which were made by the freeze-drying and subsequent closing process. The encapsulation efficiency is affected by the hollow particle morphology, amount of closing agent, exposure time, surfactant, and method of dispersing the hollow particles in water. Controlled release of procaine hydrochloride from the microcapsules into phosphate buffer was observed. The use of benign solvents dimethyl carbonate in spray/freeze-drying and CO2 for closing would eliminate concerns of residual harmful solvent in the product. The ease of separation of CO2 from the drug solution may also enable recycling of the drug solution to increase the overall encapsulation efficiency using these novel hollow particles.
590 $a School code: 0188.
650 4 $a Chemistry, Polymer. $3 1018428
650 4 $a Engineering, Chemical. $3 1018531
650 4 $a Engineering, Materials Science. $3 1017759
690 $a 0495
690 $a 0542
690 $a 0794
710 2 $a University of Rochester. $3 515736
773 0 $t Dissertation Abstracts International $g 70-10B.
790 1 0 $a Yates, Matthew Z., $e advisor
790 $a 0188
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3381740