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Improving hydraulic permeability, mechanical properties, and chemical functionality of cellulose acetate-based membranes by co-polymerization with tetraethyl orthosilicate and 3-(aminopropyl)triethoxysilane

2021; Elsevier BV; Volume: 261; Linguagem: Inglês

10.1016/j.carbpol.2021.117813

1879-1344

Mônica Calixto de Andrade, José Carlos Pereira, Nuno A.F. Almeida, Paula A.A.P. Marques, Mónica Faria, M. Clara Gonçalves,

Dielectric materials and actuators

Composite cellulose acetate (CA) membranes are widely used but their multiphase nature results in additive losses, poor mechanical strength, low chemical resistance and thermal stability, limiting their separation/purification yields. To overcome this, we fabricated monophasic hybrid membranes using a modified phase inversion technique, where tetraethylorthosilicate and 3-(aminopropyl)triethoxysilane were added to the CA casting solution. The resulting co-polymerization between CA, silanols and amine-functionalized silica groups, through sol-gel chemistry, was proved by ATR-FTIR (1118 cm−1, ν(SiOC)). The presence of propyl-amine groups increases the hydraulic permeability (3×), the rupture elongation (×1.5), and decreases the Young modulus (×1/2), due to the disruption of the CA-silica 3D network. For high propyl-amine contents this behaviour is reversed due to intensive cross-linking between CA-silica chains (decrease in 903 cm−1, ν(CH3COOC-)). The addition of silica- and amine-based structures to the CA framework increases the system degrees of freedom, opening the door to the design of new CA membranes.