Uporaba suspenzijske polimerizacije in porogenih topil za sintezo 2-hidroksietil metakrilatnih zrn

diplomsko delo univerzitetnega študijskega programa I. stopnje

Mateja Gojznikar (Author), Peter Krajnc (Mentor), Muzafera Paljevac (Co-mentor)

Abstract

V diplomskem delu smo z inverzno suspenzijsko polimerizacijo sintetizirali polimerna zrna na osnovi 2-hidroksietil metakrilata (HEMA). Sintezo smo izvedli z dvema zamreževaloma, N,N'-metilbisakril amidom (MBAA) in etilenglikol dimetakrilatom (EGDMA) ter dvema porogenima topiloma, metanol in toluen. Polimerizacijo smo sprožili termično, in sicer z dvema različnima iniciatorjema, α,α'-azoizobutilronitrilom (AIBN) in amonijevim peroksodisulfatom (APS). Pri HEMA zrnih, zamreženih z MBAA ali z EGDMA, smo variirali stopnjo zamreženosti med 20 in 60 mol%. Ugotovili smo, da v primeru uporabe MBAA kot zamreževala, dobimo z nižjo stopnjo zamreženosti zrna z večjim povprečnim premerom (470 m) in z višjo zamreženostjo zrna z manjšim povprečnim premerom (190 m). Nasprotno, smo z EGDMA dobili večja zrna z višjo stopnjo zamreženosti. Vrsta in delež uporabljenega zamreževala sta vplivala poleg velikosti nastalih zrn, tudi na obliko. Zrna pripravljena z 20 mol% EGDMA so bila bolj sferičnih oblik kot zrna pripravljena z 20 mol% MBAA. Tudi čas izvedbe reakcije lahko vpliva na obliko nastalih zrn. V našem primeru smo proučevali vpliv časa reakcije na sintezo poli(HEMA-ko-EGDMA) zrn, ki smo jo izvajali 4 oz. 8 ur. Ko smo uporabili 20 mol% EGDMA in reakcijo izvajali 4 h nismo dobili produkta. S podaljšanjem časa reakcije na 8 h, pa smo dobili kot končni produkt majhna zrna, ki so imela sferično obliko in le-tu in tam so bila zlepljena v manjše skupke. Z dodajanjem porogenega topila smo želeli vplivati predvsem na poroznost zrn ter povprečno BET površino, ki je variirala za naše vzorce brez dodatka porogena med 0,01 in 3,1 m2/g, z dodatkom porogena pa med 0,1 in 2,7 m2/g. Nabrekanje zrn smo določili v vodi, toluenu in etanolu ter ugotovili, da polimerna zrna zamrežena z 20 mol% MBAA nabrekajo v vseh testiranih topilih približno enako (stopnja nabrekanja za vodo 1,81, za toluen 2,19 in za etanol 2,06 mL/g), zrna zamrežena z 20 mol% EGDMA pa nabrekajo najbolj v etanolu in najmanj v toluenu. To je lahko posledica razlik v polarnosti topil.

Keywords

suspenzijska polimerizacija;polimerna zrna;porogena topila;porozni polimeri;

Data

Language:	Slovenian
Year of publishing:	2015
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[M. Gojznikar]
UDC:	66.095.262-911-026.743(043.2)
COBISS:	19424534
Views:	1601
Downloads:	112
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Use of suspension polymerisation and porogenic solvents for synthesis of 2-hydroxyethyl methacrylate beads DS
Secondary abstract:	In our diploma thesis we synthesized polymeric beads with inverse suspensive polymerization on the base of 2-hydroxy ethyl metacrylate (HEMA). Synthesis was conducted with two crosslinkers, N,N'-Methylenebisacrylamide (MBAA) and ethylene glycol dimethacrylate (EGDMA), and with two porogenic solvents, methanol and toluene. Polymerization was thermally initiated with two initiators, α,α’-azo-isobutyronitril (AIBN) and ammonium persulfate (APS). We varied the level of crosslinking between 20 and 60 mol% (MBAA or EDGMA). In case of the use of MBAA as a crosslinker we determined that with lower level of crosslinking we get beads with bigger average diameter (470 m) and with higher level of crosslinking we get beads with smaller average diameter (190 m). On the contrary, in the case of EGDMA, we got bigger beads with higher level of crosslinking and vice versa. Type and portion of crosslinker influenced, beside the size, also the shape of formed beads. Beads prepared with 20 mol% EGDMA were more spherical than beads prepared with 20 mol% MBAA. Time of reaction can also affect the shape of formed beads. In our case we studied the influence of the time of reaction on synthesis poly(HEMA-ko-EGDMA) beads, which was conducted for 4 or 8 hours. We did not get the product when we used 20 mol% EGDMA. With the extended time of reaction to 8 hours, we got small beads as a final product, which had spherical shape and were partially glued together into smaller conglomerations. With adding porous solvent we wanted to influence specifically on porosity of beads and average BET surface, which variated for our specimens without the addition of porogen between 0,01 and 3,1 m2/g and with the addition of porogen between 0,1 and 2,7 m2/g. We determined the swelling of beads in water, toluene and ethanol and discovered that polymeric beads crosslinked with 20 mol% MBAA swell in all tested solvents approximately the same (the level of swelling for water 1,81, for toluene 2,19 and for ethanol 2,06 mL/g), and beads crosslinked with 20 mol% EGDMA swell the best in ethanol and the least in toluene. That could be the consequence of variations in the polarity of solvents
Secondary keywords:	suspension polymerization;polymeric beads;porous polymers;porous solvents;2-hydroxyethyl methacrylate;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	XII, 40 str.
ID:	8888603