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Title:Uporaba mikroemulzij za sintezo makroporoznih polistirenskih derivatov
Authors:Orel, Matic (Author)
Krajnc, Peter (Mentor) More about this mentor... New window
Paljevac, Muzafera (Co-mentor)
Files:.pdf UN_Orel_Matic_2018.pdf (3,19 MB)
MD5: A0ABBF38321E622252B255C456288D78
 
Language:Slovenian
Work type:Bachelor thesis/paper (mb11)
Typology:2.11 - Undergraduate Thesis
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:Porozni polimerni materiali imajo širok spekter aplikacije. V kakšne namene se bo nek material uporabljal, je odvisno od mnogo dejavnikov, med drugim tudi velikost por materiala. V diplomski nalogi smo proučevali kako se premer primarnih ter sekundarnih por poli(stiren-ko-divinilbenzenskega) monolita, spreminja s hitrostjo mešanja emulzije z elektronskim mešalom in homogenizatorjem oz. z amplitudo ultrasonifikacije, ob konstantni sestavi organske ter vodne faze. PoliHIPE monolite smo pripravili s termično polimerizacijo emulzij z visokim deležem notranje faze (HIP emulzij) tipa voda v olje, katere organska faza je vsebovala monomer stiren, zamreževalodivinil benzen ter surfaktant SPAN80, vodna faza pa kalcijev klorid heksahidrat ter iniciator amonijev persulfat. Emulzijo smo zmeraj pripravili z uporabo elektronskega mešala s hitrostjo mešanja 300 obr/min, nato pa smo emulzijo mešali ali z elektronskim mešalom (med 300 in 500 obr/min), homogenizatorjem (med 3000 in 20000 obr/min) oz. z ultrasonifikacijo. Polimerizacija je potekala 24 ur pri 70 °C. Kot rezultat smo dobili monolite, katere smo okarakterizirali z vrstičnim elektronskim mikroskopom. S pomočjo SEM posnetkov smo spremljali morfologijo sintetiziranih materialov. Glavni cilj diplomske naloge je bil sintetizirati poliHIPE material s porami velikosti ≈1 μm. Najmanjša povprečna velikost primarnih por je bila ≈ 2,5 μm, ki je bila dosežena pri vzorcu katerega smo pripravili z mešanjem emulzije s homogenizatorjem s hitrostjo 15000 obr/min. Predvidevali smo, da bomo dobili najmanjše pore z uporabo ultrasonifikatorja. Najmanjše primarne pore po ultrasonifikaciji so bile velikosti 13 μm pri amplitudi 80 % in času ultrasonifikacije 4 min. Iz rezultatov je razvidno, da so se velikosti primarnih por manjšale s povišanjem števila obratov mešalnika, prav tako pa so se primarne pore manjšale s povišanjem amplitude ultrasonifikacije pri istem času ultrasonificiranja.
Keywords:mikroemulzija, makroporozni materiali, poliHIPE, HIP emulzija, radikalska verižna polimerizacija, stiren, divinilbenzen
Year of publishing:2018
Publisher:[M. Orel]
Source:Maribor
UDC:66.095.26(043.2)
COBISS_ID:21962006 New window
NUK URN:URN:SI:UM:DK:JHGSNWK6
Views:520
Downloads:100
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:KTFMB - FKKT
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Licences

License:CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
Link:http://creativecommons.org/licenses/by-nc/4.0/
Description:A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.
Licensing start date:07.09.2018

Secondary language

Language:English
Title:Use of microemulsions for the synthesis of macroporous polystyrene derivatives
Abstract:Porous polymeric materials have a wide range of applications. For what purposes a material will be used depends on many factors, including the size of the pore material. In this work we studied how the diameter of the primary and secondary pores of poly(styrene-co-divinylbenzene) monoliths varies with the rate of stirring of the emulsion by the electronic stirrer and the homogenizer, or the dependance on pore size with regards to the ultrasonification amplitude at constant composition of the organic and aqueous phase. PolyHIPE monoliths were prepared by thermal polymerization of emulsions (water-to-oil type) with a high proportion of the inner phase (HIP emulsions). The organic phase contained the monomer styrene, divinylbenzene as a crosslinker and the SPAN80 as a surfactant, while the aqueous phase consisted of calcium chloride hexahydrate and the initiator ammonium persulfate. The emulsion was always prepared using an electronic mixer with a stirring rate of 300 rpm and later on stirred with the same stirrer (300 rpm - 500 rpm), a homogenizer (3000 rpm – 20000 rpm) or was subjected to ultrasonification (40 % to 80 % amp.). The polymerization took place at 70 ° C for 24 hours. As a result, we obtained monoliths, which were characterized by an electron microscope. With the help of the resultant electron microscope images we monitored the morphology of synthesized materials. The main goal of this work was to synthesize polyHIPE material with an average pore size of ≈1 μm. The minimum average primary pore size was ≈ 2.5 μm, which was obtained with the sample prepared by stirring the emulsion with the homogenizer at a speed of 15000 rpm. We assumed that we would get the smallest pores using an ultrasonificator. The smallest primary pores after ultrasonification were 13 μm in size and made at 80 % amplitude and 4 minutes ultrasonification time. From the results it can be seen that the sizes of primary pores decreased with an increase in the number of rpm of the stirrer. Primary pore size also decreased with an increase in the ultrasonification amplitude at the constant ultrasonification time.
Keywords:microemulsions, macroporous materials, polyHIPE, HIP emulsions, radical chain polymerization, styrene, divinylbenzene


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