SYNTHESIS AND CHARACTERIZATION OF THERMORESPONSIVE COMPOSITE PATCHES BASED ON GELLAN GUM, CHITOSAN, AGAR, AND POLY(2-OXAZOLINE) DERIVATIVES

Abstract

Biodegradable polymer composites were developed using gellan gum, agar–agar, and chitosan as natural matrices, with poly(2-ethyl-2-oxazoline) (PEOZ, 0.15 g) added as a functional modifier. Four film types (GG–Ch, GG–Ch–Ox, A–Ch, A–Ch–Ox) were evaluated for structural and physicochemical performance. The films showed thicknesses of 0.1648–0.3455 mm and masses of 3.70–5.68 g. Incorporation of PEOZ significantly improved folding endurance, increasing it from 68 to 90 cycles in gellan–chitosan and from 42 to 76 cycles in agar–chitosan composites. Swelling and sol–gel analyses revealed higher crosslinking density and lower soluble fraction in modified samples. FTIR spectra confirmed hydrogen bonding and electrostatic interactions, while SEM-EDS of GG–Ch–Ox demonstrated a homogeneous surface with Na⁺/Cl⁻ distribution, indicating efficient ionic crosslinking. The modified systems exhibit improved mechanical stability, water retention, and morphological uniformity, making them promising candidates for biomedical uses such as wound dressings and transdermal patches.