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Title:Vpliv naknadnega zamreženja poli(4-vinilbenzil klorida) na strukturo in površino.
Authors:Turnšek, Marko (Author)
Krajnc, Peter (Mentor) More about this mentor... New window
Files:.pdf UNI_Turnsek_Marko_2010.pdf (2,14 MB)
 
Language:Slovenian
Work type:Undergraduate thesis (m5)
Organization:FNM - Faculty of Natural Sciences and Mathematics
Abstract:V diplomskem delu predstavljamo vpliv naknadnega zamreženja poli(4-vinilbenzil klorida) na njegovo strukturo. Porozni polimeri so bili pripravljeni s polimerizacijo v masi. Polimerizacija v masi poteka tako, da zmešamo monomer, zamreževalo in porogen ter dodamo iniciator in sprožimo polimerizacijo. Uporabili smo 4-vinilbenzil klorid kot monomer, kot zamreževalo je bil uporabljen divinilbenzen. Poiskati je bilo potrebno ustrezen porogen; najustreznejši je bil cikloheksan. Najti je bilo potrebno tudi primerno razmerje med monomerom in zamreževalom, ki je bilo 60:40 masnih odstotkov, v drugih primerih monolit ni nastal ali pa je prekomerno razpokal pri čiščenju. Kot radikalski iniciator je bil uporabljen azobisizobutironitril. Polimerizirali smo v plastičnem kalupu, pri povišani temperaturi (približno 60°C), ker je v tem območju delovanje iniciatorja optimalno. Polimer smo naknadno zamrežili s Friedel—Craftsovo reakcijo. Kot katalizator za to reakcijo smo uporabili FeCl3. Čas reakcije je bil pomemben faktor, saj smo z njim vplivali na stopnjo naknadnega zamreženja. Dlje časa je reakcija potekala, bolj se je povečala specifična površina polimera. Polimere je bilo potrebno očistiti s primernim topilom. Z elektronsko mikroskopijo smo preverili, če so se strukture polimerov pred in po reakciji spremenile. Z BET metodo smo določili specifično površino pred in po naknadnem zamreženju, določili smo tudi odstotek klora pred in po reakciji in z infrardečo spektroskopijo preverili kemijsko strukturo polimera. Opaziti je bilo, da se struktura materiala ni spremenila, povečala pa se je specifična površina. Posledično se je s povečanjem površine spremenila količina klora pri vsakem vzorcu in sicer z večanjem specifične površine se manjša količina klora, saj se klorometilni mostovi spremenijo v metilenske mostove.
Keywords:Ključne besede: polimeri, polimerizacija v masi, zamreženi polimeri, naknadno zamreženje, hiperzamreženje, monolit, VBC, 4-vinilbenzil klorid.
Year of publishing:2010
Publisher:[M. Turnšek]
Source:Maribor
UDC:54(043.2)
COBISS_ID:17846024 Link is opened in a new window
NUK URN:URN:SI:UM:DK:QY2X03ZL
Views:2558
Downloads:294
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Categories:FNM
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Secondary language

Language:English
Title:Influence of hypercrosslinking of poly(4-vinylbenzyl chloride) on structure and surface area.
Abstract:ABSTRACT In this graduation thesis we present the influence of hypercrosslinking of poly(4-vinylbenzyl chloride) on its structure. Porous polymers were created by bulk polymerisation. Bulk polymerisation is utilised by mixing the monomer, crosslinker and porogen and then adding the initiator, thus triggering the polymerisation. We used 4-vinylbenzyl chloride as the monomer and divinylbenzyl as the crosslinker. We had to find a suitable porogen; the best suited was cyclohexane. We also had to determine the appropriate ratio between the monomer and crosslinker, which was 60:40 percent by mass, in other cases monolith was not created or it prematurely cracked during cleaning. For a radical initiator we used azoisobutyronitrile. Polymerisation took place in a plastic mold at an elevated temperature (approximately 60 degrees Celzius), because this is the optimal working range for this initiator. The polymer was subsequently crosslinked by Friedel-Crafts reaction, with FeCl3 as the catalyst. The reaction time was a critical factor, as we used it to influence the degree of subsequent crosslinking. The longer the reaction the larger the internal surface of the polymer. Polymers had to be cleaned with the appropriate solvent. Electronic microscope was used to examine any changes in the structure of polymers before and after the reaction. With the BET method we defined the specific surface before and after the subsequent crosslinking, and the percentage of chlorine before and after the reaction; we used infrared spectroscopy to determine the chemical structure of the polymer. We could see that the morphology of the material was unchanged; however, the specific surface did enlarge. Therefore, as the surface enlarged, we could also detect a change in the concentration of chlorine in each sample; as the surface enlarged the quantity of chlorine declined, because the chloromethyl bridges turned into methylene bridges.
Keywords:polymers, bulk polymerization, crosslinked polymers, subsequent crosslinking, monolith, VBC, 4-vinylbenzyl chloride.


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