Strukturiranje polimernih mreža na osnovu akrilamida i akrilne kiseline

Abstract

U ovom radu sintetisani su hidrogelovi na osnovu akrilamida i akrilne kiseline, radikalnom polimerizacijom, primenom konvencionalne i mikrotalasne metode sinteze. Varirani su početni odnosi monomera i udeo umreživača, u cilju ispitivanja uticaja sastava reakcione smeše na svojstva dobijenih hidrogelova. Optimizovani su uslovi sinteze u mikrotalasnom polju kao brže, jednostavnije i ekonomičnije metode. U cilju uspostavljanja korelacije između mehanizma sinteze, strukture i svojstava dobijenih hidrogelova, primenom relevantnih metoda karakterizacije, upoređena su apsorpciona, reološka, toplotna i strukturna svojstva hidrogelova dobijenih dvema metodama. Ustanovljeno je da se mikrotalasnom metodom sinteze na brži i jednostavniji način uz smanjen utrošak vremena i energije dobijaju hidrogelovi konkurentni onima koji se dobijaju konvencionalnim zagrevanjem u vodenom rastvoru. Drugi deo doktorata obuhvata sintezu hidrofilnih polimernih mreža na osnovu natrijum karboksimetilceluloze (NaCMC) i karboksilnih kiselina, od kojih je jedna serija sintetisana prožimanjem linearnim kopolimerima akrilamida i akrilne kiseline u cilju povećanja potencijala primene u floku-lacione svrhe. Rezultati ispitivanja svojstava bubrenja, strukturnih toplotnih i flokulacionih svojstava pokazali su međusobno slaganje. Dobijeni rezultati pokazali su da od primenjenih karboksilnih kiselina, linunska kiselina u udelu od 15% u odnosu na masu NaCMC daje hidrogelove najboljih svojstava. Kombinacijom ove mreže sa kopolimerom akrilamida i akrilne kiseline u masenom odnosu 10/90, stvara se teorijska platforma za dobijanja flokulanta koji bi mogao da pokaže visoku efikasnost u prečišćavanju vode u kojoj dominiraju pozitivno naelektrisane čestice, pravilnim izborom parametara flokulacije.

In this paper, hydrogels based on acrylamide and acrylic acid were synthesized using conventional and microwave synthetic methods via free-radical polymerization. The initial monomers ratio and amount of crosslinking agent were varied in order to investigate the effect of the composition of the reaction mixture on the properties of the obtained hydrogels. The conditions of synthesis in the microwave field as faster simpler and more economical method have been optimized. In order to establish a correlation between the mechanism of synthesis, structure and properties of the obtained hydrogels using the relevant methods of characterization, the absorption, rheological, thermal and structural properties of the hydrogels obtained by the two methods were compared. It has been found that the microwave synthesis is a faster and simpler method, which enables reduced consumption of time and energy and produces hydrogels competitive to those ones obtained by conventional heating in aqueous solution. The second part of the thesis includes the synthesis of hydrophilic polymer networks based on sodium carboxymethylcellulose (NaCMC) and carboxylic acids, whereby one series is synthesized by interpenetration of the network using the linear acrylamide and acrylic acid copolymers in order to increase the potential application of hydrogels for flocculation purposes. The results of measurements of swelling, structural, thermal and flocculation properites have shown mutual agreement. The obtained results have shown that among applied carboxylic acids, citric acid in the amount of 15% per mass of NaCMC, has given the hydrogels with the best properties. The Combination of this network with a copolymer of acrylamide and acrylic acid in a mass ratio of 10/90 has created a theoretical platform for the production of flocculant which could show high efficacy in purifying of water dominated by positively charged particles.