Development of starch-based bioaerogels with microfibrillated cellulose for potential application as CO2 adsorbent
Name: CARLOS VINICIUS FARIAS GAMA
Publication date: 28/04/2026
Examining board:
Name |
Role |
|---|---|
| CLEOCIR JOSE DALMASCHIO | Examinador Interno |
| ELOILSON DOMINGOS | Examinador Externo |
| MARTA ALBUQUERQUE MACHADO | Presidente |
Summary: Starch stands out as a promising biopolymer for replacing non-biodegradable polymers. However, its application is limited by mechanical brittleness, low thermal stability, and high-water affinity. In this study, the crosslinking of starch with citric acid and the incorporation of microfibrillated cellulose (MFC) into the matrix were adopted as strategies to minimize these limitations, establishing a stable polymer network capable of reducing hygroscopicity and increasing the thermal and mechanical properties of the material. First, the crosslinked starch was prepared and characterized to evaluate structural, thermal, and rheological changes as a function of citric acid concentration (1, 3, and 5% w/w). FTIR and XRD analyses confirmed the formation of ester bonds, with the appearance of a characteristic band near 1720 cm-1 for samples crosslinked with 3 and 5% citric acid, and a decrease in the intensity of starch crystalline peaks as the crosslinker concentration increased. TGA and DSC analyses showed significant changes in thermal behavior, exhibiting higher residual mass, higher maximum degradation temperature, and lower gelatinization enthalpy compared to the control starch. The sample containing 3% citric acid presented the highest yield stress (0 = 278.04 ± 11.87 Pa) and was selected to produce crosslinked bioaerogels reinforced with microfibrillated cellulose, in which the effects of MFC concentration and refining degree were investigated. The results demonstrated that the incorporation of cellulose promoted greater mechanical strength, higher thermal stability, and moderate moisture absorption. The sample with a higher refining degree and lower concentration stood out for exhibiting high porosity (90.99%), higher maximum degradation temperature (324.24 °C) compared to the pure starch aerogel, greater mechanical strength, lower moisture absorption (< 10%), and higher CO adsorption capacity (14.74 mg·g-1). The Avrami fractional-order kinetic model provided the best fit to the adsorption data (R2 > 0.99). Functionalization did not maximize the adsorption capacity, although it presented different mechanisms during the adsorption process, suggesting further investigations.
