| Summary: Use of polyelectrolyte complexes prepared by mixing anionic and cationic polyelectrolytes have grown rapidly in the large scale industrial applications, such as coatings, binders, flocculants, as well as in biotechnical and biomedical applications recently. In this thesis, preparation of biopolyelectrolyte complexes (BPEC) from different biopolyelectrolytes and their applications as a dry strength additive for papermaking were investigated in detail. BPECs will be produced by mixing anionic and cationic biopolyelectrolytes with different molecular weight and charge density. Starches, carboxymethyl celluloses (CMC), and chitosans were used as biopolyelectrolytes. The effects of concentration of biopolyelectrolyte solution,dosage rate, charge ratio, and mixing rate on BPEC properties will be studied. Average diameter, zeta potential and charge density were used to characterize BPEC particles. Chitosan were modified with glycidyltrimtrimethylammonium chloride to give quaternary ammonium groups to the structure. Therefore, with this modification the solubility and cationic charges of chitosan were improved. The BPEC’s were produced by using cationic starch-anionic starch, cationic starch-CMC, and cationic starch-CMC couples. The produced BPEC’s were added to paper to test their performance as a dry strength additive. The results showed that BPECs were higher performance comparing to the single addition of biopoliyelectrolyte at the same addition level.
Key words: Biyopolyelectrolyte complex, chitosan, starch, carboxy methyl cellulose, dry strength
|
