SYNTHESIS OF HYBRID MESOPOROUS POLYSTYRENE-SILICA MATERIALS WITH NON-SURFACTANT CITRIC ACID AS TEMPLATE VIA SOL-GEL PROCESS

Hybrid mesoporous polystyrene-silica materials were successfully prepared through HCl-catalyzed sol-gelreactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radicalpolymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent andfollowed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy(IR), N_2 adsorption-desorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) andtransmission electron microscopy (TEM). The results indicate that the materials prepared with 50 wt%-60 wt% templatecontents have average pore sizes of 2-3 nm and large surface areas (ca. 886 m~2/g) as well as high pore volumes (ca.0.53 cm~3/g). The mesoporosity arises from interconnected channels and pores with disordered arrangements. The porediameters and pore volumes increase as the template content is increased. The pore diameters show a little change uponheating at 200℃ overnight. However, the materials do not have good hydrothermal stability.

SYNTHESIS OF HYBRID MESOPOROUS POLYSTYRENE-SILICA MATERIALS WITH NON-SURFACTANT CITRIC ACID AS TEMPLATE VIA SOL-GEL PROCESS*

 Hybrid mesoporous polystyrene-silica materials were successfully prepared through HCl-catalyzed sol-gelreactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radicalpolymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent andfollowed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy (IR), N₂ adsorption-desorption measurements,powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM).The results indicate that the materials prepared with 50 wt%-60 wt% template contents have average pore sized of 2-3 nm and large surface areas(ca.886 m²/g) as well as high pore volumes (ca.0.53 cm³/g) The mesoporosity arises from interconnected channels and pores with disordered arrangements.The pore diameters and pore volumes increase as the template content is increased.The pore diameters show a little change upon heating at 200℃ overnight.However,the materials do not have good hydrothermal stability.