Porous beads from multiple emulsions with thiol-ene polymerisation

magistrsko delo

Stanko Kramer (Author), Peter Krajnc (Mentor), Muzafera Paljevac (Co-mentor)

Abstract

This thesis aims to explain the process of porous bead synthesis. The porous beads were prepared from a multiple emulsion water-in-oil-in-water (W/OW) system. The W/O/W multiple emulsion was made up of a High Internal Phase Emulsion (HIPE (primary emulsion)) and a suspension phase. The HIPE consisted of pentaerythritol tetrakis (3 mercaptopropionate) (TT) in combination with either divinyl adipate (DVA) or trimethylolpropane triacrylate (TMPTA) and an internal phase volume fraction of 80 %. The suspension phase consisted of an aqueous phase with dissolved surfactants which stabilised the secondary emulsion. The surfactants which stabilised the secondary emulsion were polyvinylpyrrolidone K30 (PVP K30) and polyvinylpyrrolidone K90 (PVP K90). The polymerisation was carried out thermally at first for 24 hours and later under UV light and daylight, as the thermally initiated polymerisation was unsuccessful due to coalesence. The beads that were obtained using the photoinitiated polymerisation were porous with a mostly bicontinuous structure and varying diameters. The viscosity of the primary emulsion (HIPE) had the greatest influence on the stability of the entire W/O/W emulsion. By adding more than 5 wt. % of toluene to the primary emulsion, the emulsion broke down and did not successfully polymerise. Another important factor was the ratio of the functional groups in the case of TT-co-TMPTA, which greatly affected the yield and structure of the obtained beads. The diameters of the spherical particles were dependent on the viscosity, monomer ratio and surfactant used in the suspension phase. The inner structure of the beads was mostly bicontinuous with occasional pores that resembled a polyHIPE structure. The obtained beads had a yield of up to 80 % in the case of TT-co-DVA and a yield of up to 90 % in the case of TMPTA-co-DVA

Keywords

polyHIPE;thiol-ene;suspension polymerisation;porous beads;HIPE;magistrske naloge;

Data

Language:	English
Year of publishing:	2019
Typology:	2.09 - Master's Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[S. Kramer]
UDC:	66.095.262(043.2)
COBISS:	22600982
Views:	858
Downloads:	152
Average score:	0 (0 votes)
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Other data

Secondary language:	Slovenian
Secondary title:	Porozna zrna iz multiplih emulzij s tiol-en polimerizacijo
Secondary abstract:	V magistrskem delu smo razložili in opisali postopek sinteze poroznih zrn. Porozna zrna smo pripravili iz voda-v-olju-v-vodi (V/O/V) multiplih emulzij. V/O/V emulzija je bila sestavljena iz emulzije z visokim deležem notranje faze (HIPE (primarna emulzija)) in suspenzijske faze. HIPE je bil sestavljen iz pentaeritritol tetrakis (3-merkaptopropionat) (TT) in divinil adipata (DVA) ali trimetilolpropan triakrilata (TMPTA) ter notranje faze z 80 % volumskim deležem. Suspenzijska faza je vsebovala vodno fazo z raztopljenim surfaktantom, ki je stabiliziral sekundarno emulzijo. Surfaktanti, ki so stabilizirali sekundarni emulzijo so bili polivinilpirolidon K30 (PVP K30) in polivinilpirolidon K90 (PVP K90). Najprej smo polimerizacijo izvedli termično pri temperaturi 60 °C v 24 urah. Ta oblika polimerizacije ni bila uspešna zaradi aglomeracije, zato smo kasneje izvajali polimerizacijo pri dnevni in UV svetlobi. Zrna, ki smo dobili z uporabo fotopolimerizacije, so bila porozna z bikontinuirno strukturo in različnimi premeri. Na stabilnost V/O/V emulzije je imela največji vpliv viskoznost primarne emulzije (HIPE). Ko smo k prvotni emulziji dodali toluen, kateraga masa je bila 5 % mase emulzije, je emulzija razpadla in polimerizacija ni bila uspešna. Poleg viskoznosti je bil pomemben faktor tudi razmerje funkcionalnih skupin v primeru sinteze zrn iz TT in TMPTA, saj je vplivalo na izkoristek reakcije. Premeri sferičnih zrn so bili odvisni od viskoznosti, razmerij monomerov in surfaktanta v suspenzijski fazi. Notranja struktura zrn je bila večinoma bikontinuirna z občsanimi porami, podobnim poram pri poliHIPE strukturi. Dobljena zrna so imela izkoristke polimerizacije do 80 % v primeru TT-ko-DVA in tudi do 90 % v primeru TT-ko-TMPTA.
Secondary keywords:	poliHIPE;tiol-en;suspenzijska polimerizacija;porozna zrna;HIPE;
Type (COBISS):	Master's thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	XI, 51 str.
ID:	11208452