Abstract:
In the present work, a series of ordered amine-functionalized mesoporous silicas (HMS-NH2) and natural rubber/mesoporous silica composites (NR/HMS-NH2) were synthesized via direct co-condensation and sol-gel method under neutral conditions using tetraethyl orthosilicate (TEOS) as a silica precursor, and tetrahydrofuran was used as organic solvent to control interaction and sol-gel reaction of silica source and aminosilanes. Dodecylamine (DDA) was used as a structure-directing agent in the presence of 3-aminopropyltrimethoxysilane (APS), [amino-ethylamino] propyltrimethoxysilane or [(2aminoethylamino)ethylamino]propyltrimethoxysilane (AEEA) as amino group precursors. Effects of aging temperature, aging time, type and concentration of the added aminosilanes on the physicochemical properties of the resulting materials were investigated by using various characterization techniques. The results confirmed the synthesis of successful amine-functionalized mesoporous silicas and natural rubber/mesoporous silica composites with different amine groups. Their mesostructured framework was retained even after the functionalization at a high APS loading level (15 mol%) or using AEEA as the aminosilane precursor. The HMS-NH2 materials has an amine concentration of 0.722.16 mmol g-1 , a high surface area (272-627 m2 g-1) and a large total pore volume (0.48-1.92 cm3 g-1). Besides, the NR/HMS-NH2 obtained an amine concentration of 0.431.84 mmol g-1, high surface area (115-492 m2 g-1) and a large total pore (0.14-1.34 cm3 g-1). In addition, their hydrophobicity was confirmed by contact angle measurement.