Synthesis of novel stimuli-responsive hydrogels based on polyurethane

AXEL J. CIMAS; FRANCISCO M. PARDINI; JAVIER I. AMALVY

INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2024

1023-666X

This article describes the study ofa thermo-responsive hybrid systems based on polyurethane (PU) modified with sensitiveacrylamide derivates.The hybrid systems were synthesizedusing PU and two acrylamide derivatives (N-isopropylacrylamide (NIPA)and N-isopropylmethacrylamide (NIPMA)) in different proportions. Thesystems were characterized using Infrared Spectroscopy (FTIR), ThermogravimetricAnalysis (TGA), Differential Scanning Calorimetry (DSC), and Dynamic LightScattering (DLS). Water-uptake capacity and sedimentation rate were alsodetermined.The results showed that the hybrids with 30 % acrylamide derivate (AD) showed a T50 ofapproximately 360 °C indicating that thermal degradation decreased with theaddition of NIPA and NIPMA. Additionally, the incorporation of AD increasesthe glass transition temperature from -34 to -22°C when 30% AD was used.The hybrids with 30 % AD showed avariation in the diameters (above 60 %) when the temperature was decreased from50 to 22 °C. These changeswere attributed to the hydrophilic → hydrophobic transition that occurs whenmeasuring below and above the low critical solution temperature(LCST) of thepolymer. Furthermore,the extra methyl group in the structure of NIPMA makes the collapse lesspronounced than in NIPA, decreasing the relative diameter change by 10 %.