The effect of the molecular structure of hydroxypropyl methylcellulose on the states of water, wettability, and swelling properties of cryogels prepared with and without CaO2

Author(s)

Chiaregato, Camila Gruber ; Bernardinelli, Oigres Daniel ; Shavandi, Amin ; Sabadini, Edvaldo ; Petri, Denise Freitas Siqueira

• Document type: Journal article
• Source: Carbohydrate Polymers; v. 316, p. 10-pg., 2023-05-20.

Abstract

Hydroxypropyl methylcellulose (HPMC) belongs to the cellulose ether family that has hydroxyl groups substituted by hydrophobic methyl groups (DS) and hydrophilic hydroxypropyl groups (MS). Herein, the in-teractions between water molecules and cryogels prepared with HPMC in the presence and absence of a linear nonionic surfactant, as well as CaO2 microparticles, which react with water producing O2, were systematically investigated by sorption experiments and Time-Domain Nuclear Magnetic Resonance. Regardless of the DS and MS, most water molecules presented transverse relaxation time t2 typical of intermediate water and a small population of more tightly bound water. HPMC cryogels with the highest DS of 1.9 presented the slowest swelling rate of 0.519 +/- 0.053 gwater/(g.s) and the highest contact angle values 85.250o +/- 0.004o, providing the best conditions for a slow reaction between CaO2 and water. The presence of surfactant favored hydrophobic in-teractions that allowed the polar head of the surfactant to be exposed to the medium, resulting in a higher swelling rate and lower contact angle values. The HPMC with the highest MS presented the fastest swelling rate and the lowest contact angle. These findings are relevant for the formulations and reactions, where tuning the swelling kinetics is crucial for the final application. (AU)

• FAPESP's process: 18/13492-2 - Synthetic and natural scaffolds applied to regenerative medicine
• Grantee: Luiz Henrique Catalani
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/06284-0 - Cellulose ether, biomass and calcium peroxide based cryogels for the removal of drugs and oxygen release in aqueous medium
• Grantee: Camila Gruber Chiaregato
• Support Opportunities: Scholarships in Brazil - Doctorate