Synthesis and properties of methacrylic acid based hydrogels modified with zeolites

[V. V. Panić]

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Hemija i hemijska tehnologija - Hemijska tehnologija / Chemistry and Chemical Technology - Chemical Technology

U prvom delu ovog rada sintetisani su hidrogelovi na bazi delimično i potpuno neutralisane metakrilne kiseline, radikalnom polimerizacijom i umrežavanjem na 80 °C, konvencionalno i pod dejstvom mikrotalasnog polja. Primenom ova dva načina sinteze i variranjem eksperimentalnih parametara, sintetisani su makroporozni materijali sa veoma različitim karakteristikama, morfologijom, osnovnim strukturnim parametrima, mehaničkim svojstvima i ponašanjem pri bubrenju, što je pokazano njihovim karakterisanjem primenom infracrvene spektroskopije sa Furijeovom transformacijom (FTIR), skenirajude elektronske mikroskopije (SEM), dinamičko-mehaničke analize (DMA) i pradenjem kinetike bubrenja. Nakon analize i optimizacije dobijenih rezultata, konvencionalnom radikalnom polimerizacijom su sintetisani kompozitni hidrogelovi na bazi PMAA matrice sa stepenom neutralizacije monomera od 80% i neorganskih punila, tipa zeolita A i ZSM-5 u koncentracijama 10-30 mas%. Karakterisanje dobijenih kompozita izvršeno je FTIR, DMA i termogravimetrijskom analizom (TGA), SEM mikroskopijom i pradenjem ponašanja pri bubrenju i dehidrataciji pod uticajem različitih eksperimentalnih uslova: pH medijuma, temperature, dejstva ultrazvučnog i mikrotalasnog polja. Utvrđeno je da je zeolit ravnomerno raspoređen u PMAA matrici, kao i da su ostvarene interakcije fizičke, najverovatnije vodonične veze. Utvrđeno je i da su sintetisani kompoziti boljih mehaničkih svojstava, bržeg odziva i vede termičke stabilnosti, pH-osetljivi, dok su u ispitivanom temperaturnom opsegu potpuno neosetljivi na promenu temperature ukoliko nisu izloženi dejstvu utrazvučnog ili mikrotalasnog polja. Ispitana je mogudnost uklanjanja katjonske boje basic yellow 28 (BY28) sorpcijom iz vodenih rastvora na sintetisanim hidrogelovima, kao i uticaj stepena neutralizacije monomera, prisustva, vrste i koncentracije zeolita u kompozitnim hidrogelovima na uspešnost uklanjanja navedene boje, pod različitim eksperimentalnim uslovima, kao i kinetika sorpcije i adsorpcione izoterme. Pokazano je da su sintetisani materijali pogodni za uklanjanje BY28 i da su uspešnost i tok procesa sorpcije uslovljeni vrstom sorbenta i primenjenim uslovima...

In the first part of this work hydrogels based on partially and completely neutralized methacrylic acid were synthesized by free-radical polymerization and crosslinking at 80 °C, conventionally and in microwave field. By using these two methods of synthesis and by varying the experimental parameters, macroporous materials with very different characteristics, morphology, the basic structural parameters, mechanical properties and swelling behavior, were synthesized as demonstrated by characterizing them using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Dynamic-mechanical analysis (DMA) and by monitoring the kinetics of swelling. After analysis and optimization of the obtained results composite hydrogels based on PMAA matrix with the neutralization degree of monomer of 80% and inorganic fillers, of zeolite A and ZSM-5 type at concentrations of 10-30 wt% were synthesized conventionally. The characterization of the obtained composites was performed by FTIR, thermogravimetric (TGA) and DMA analysis, SEM microscopy and by monitoring the swelling behavior and dehydration at different solution pH, temperature and under effects of ultrasonic and microwave fields. It is found that the zeolite particles are distributed uniformly in the PMAA matrix and that the established interactions are physical, probably hydrogen bonds. It is also found that the composites with better mechanical properties and higher thermal stability, sensitive to change of solution pH, while completely insensitive to temperature changes in the investigated temperature range unless they are exposed to ultrasound or microwave field, were synthesized. The possibility of removing of the cationic dye basic yellow 28 (BY28) from wastewater by sorption onto synthesized hydrogels, and the effect of the monomer neutralization degree, presence, type and concentration of zeolite in the hydrogels, on the efficiency of the removal of BY28 under different experimental conditions, were investigated, as well as sorption kinetics and isotherms. It is shown that the synthesized materials are suitable for the removal of BY28 and that the efficiency and progress of sorption process is affected by the type of the sorbent and the conditions applied...

methacrylic acid, zeolites, composites, swelling of the hydrogels, ultrasonic field, microwave field, sorption

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