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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Katijonizuoti ir polietilenglikoliu modifikuoti chitozano dariniai bei nanodalelės / Cationized and poly(ethylene glycol) modified chitosan derivatives and nanoparticles

Gruškienė, Rūta 02 July 2010 (has links)
Pagrindinis šio darbo tikslas buvo susintetinti vandenyje tirpius norimos struktūros bei skirtingo pakeitimo laipsnio skiepytuosius chitozano-polietilenglikolio (MPEG) kopolimerus bei katijonizuotus chitozano darinius ir ištirti jų savybes. „Klik“ chemijos reakcijų pagalba susintetinti nauji įvairaus pakeitimo laipsnio chitozano-MPEG skiepytieji kopolimerai, turintys triazolilliekaną. Pasiūlyti nauji chitozano-C(6)-MPEG bei N-2,3-epoksipropil-N,N,N-trimetilamonio chloridu C(6)-katijonizuoto chitozano sintezės būdai, chitozano aminogrupių apsaugai naudojant chitozano kompleksus su dodecilsulfatu. Dalinai N-katijonizuoto chitozano darinius papildomai katijonizuojant šarminėje terpėje, gauti N,O-katijonizuoti chitozano dariniai, turintys labai didelį katijonizavimo laipsnį. Pasiūlytas katijonizuoto chitozano fermentinės hidrolizės metodas, kurį naudojant chitozano darinio molekulinę masę lengvai galima sumažinti dešimtimis kartų. Chitozaną modifikuojant vyno, citrinų, adipo rūgštimis, susintetinti dalinai tinklinti chitozano dariniai. Prie chitozano ir karboksirūgštimis modifikuotų chitozano nanodalelių prijungus (4-cianpentano rūgšties)-4-ditiobenzenkarboksilatą, susintetintas makroiniciatorius gyvybingajai radikalinei polimerizacijai RAFT metodu. / The main aim of this work was to synthesize water-soluble chitosan-methoxy poly(ethylene glycol) (MPEG) graft copolymers and quaternized derivative of chitosans of various structure and desirable graft density and to study their properties. Novel chitosan-MPEG derivatives containing triazolyl moiety with different degree of substitution of chitosan were prepared for the first time by “click chemistry”. Several new schemes of the synthesis of chitosan-C(6)-TMPEG and C(6)-quaternized chitosan derivatives were suggested based on protection of amino functionality by using chitosan-dodecyl sulfate complexes. Additional cationization of cationic chitosan through its hydroxyl groups in alkaline medium enabled to prepare N,O-quaternized chitosans derivatives with very high degree of quaternization. It was suggested method of enzymatic hydrolysis of quaternized chitosans which allow a tenfold decrease the molecular weight of chitosans derivatives. Modification of chitosan by tartaric, citric or adipic acid yielded partially crosslinked chitosan derivatives. Modification of chitosan and further modification of chitosan nanoparticles by dithiobenzendicarboxylate resulted in RAFT macroinitiators which are precursors of functionalized nanoparticles.
2

Cationized and poly(ethylene glycol) modified chitosan derivatives and nanoparticles / Katijonizuoti ir polietilenglikoliu modifikuoti chitozano dariniai bei nanodalelės

Gruškienė, Rūta 02 July 2010 (has links)
The main aim of this work was to synthesize water-soluble chitosan – methoxy poly(ethylene glycol) (MPEG) graft copolymers and cationized chitosan derivatives of various structure and desirable graft density, and to study their properties. Novel chitosan-MPEG derivatives with different degree of substitution of chitosan were prepared for the first time by “click” chemistry. Several new schemes of the synthesis of chitosan-MPEG and additionally cationized chitosan derivatives were suggested based on protection of amino functionality by using chitosan-dodecyl sulphate complexes. Additional cationization of chitosan through its hydroxyl groups in alkaline medium enabled to prepare chitosan derivatives with very high charge density. A method of enzymatic hydrolysis of the cationized chitosans was proposed which allowed a tenfold decrease of the molecular weight of chitosan derivatives. Modification of chitosan by tartaric, citric or adipic acid yielded chitosan nanoparticles. Further modification of chitosan nanoparticles by dithiobenzendicarboxylate resulted in RAFT macroinitiators used as precursors of functionalized nanoparticles. / Pagrindinis šio darbo tikslas buvo susintetinti vandenyje tirpius norimos struktūros bei pakeitimo laipsnio skiepytuosius chitozano – polietilenglikolio (MPEG) kopolimerus bei katijonizuotus chitozano darinius ir ištirti jų savybes. Įvairaus pakeitimo laipsnio chitozano-MPEG skiepytieji kopolimerai susintetinti vykdant „klik“ chemijos reakcijas. Pasiūlyti nauji chitozano-MPEG bei papildomai katijonizuoto chitozano sintezės būdai, chitozano aminogrupių apsaugai naudojant chitozano kompleksus su dodecilsulfatu. Dalinai katijonizuoto chitozano darinius papildomai katijonizuojant šarminėje terpėje, gauti chitozano dariniai, turintys labai didelį krūvio tankį. Pasiūlytas katijonizuoto chitozano fermentinės hidrolizės metodas, kurį naudojant chitozano darinio molekulinę masę lengvai galima sumažinti dešimtimis kartų. Chitozaną modifikuojant vyno, citrinų arba adipo rūgštimis, susintetintos nanodalelės. Prie chitozano nanodalelių prijungus (4-cianpentano rūgšties)-4-ditiobenzenkarboksilatą, susintetintas makroiniciatorius gyvybingajai radikalinei polimerizacijai RAFT metodu.

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