Author(s):
1. Ivan Ristić, Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Serbia
2. Vladan Mićić, Faculty of Technology - University of East Sarajevo, Republic of Srpska, Bosnia and Herzegovina
3. Jelena Tanasić, Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Serbia
4. Marija Kostić, Univerzitet u Novom Sadu, Tehnološki fakultet, Novi Sad, Serbia
5. Svetlana Pelemiš, Faculty of Technology - University of East Sarajevo, Republic of Srpska, Bosnia and Herzegovina

Abstract:
This study explores a fast and efficient microwave-assisted method for synthesizing sodium alginate (SA) hydrogels crosslinked with citric acid (CA), at mass fractions of 5, 10, and 15%. For comparison, conventional chitosan (CH)–alginate hydrogels were also prepared. While CH–SA systems are widely studied, microwave-synthesized CA–SA hydrogels remain largely unreported. Complete crosslinking of SA with CA was achieved within 7 minutes under microwave irradiation, whereas conventional heating led to incomplete gelation and structural disintegration. The resulting CA–SA hydrogels demonstrated pH-responsive swelling behavior, with the highest swelling observed at 15% CA and good structural stability across the pH range 3–8. FTIR spectra confirmed ester bond formation, while DSC analyses indicated increasing glass transition temperatures (Tg) with CA content (12–33 °C). Compared to CH–SA hydrogels, which exhibited optimal swelling at a 1:1 ratio and higher Tg values (50–57 °C), the CA–SA hydrogels offer tunable swelling characteristics and significantly reduced synthesis time. These findings highlight the potential of microwave-assisted CA–SA hydrogels as sustainable, pH-responsive materials for applications such as controlled drug delivery, with future work directed toward improving their mechanical robustness.

Key words:
green polymers,microwave-assisted synthesis,biopolymers,hydrogels

Date of abstract submission:
17.07.2025.

Conference:
Contemporary Materials 2025 - Savremeni Materijali