SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS

Mesoporous poly(styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis was achieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymer in the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template or pore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder X-ray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m(2)/g) and pore volumes (e.g. 0.6 cm(3)/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, pore volumes and pore diameters of the hybrid materials increase.

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-gel reactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radical polymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent and followed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy OR), N-2 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 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 pore diameters and pore volumes increase as the template content is increased. The pore diameters show a little change upon heating at 200degreesC overnight. However, the materials do not have good hydrothermal stability.

TARTARIC ACID TEMPLATED SYNTHESIS OF MESOPOROUS Ti-INCORPORATED SILICA AND ITS CATALYTIC ACTIVITY FOR THE RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE

Ti-incorporated mesoporous silica materials with pore diameters of 3-4 nm have been prepared via the co-hydrolysis and co-condensation reactions, that is the sol-gel reactions, of titanium (IV) tetrabutoxide and tetraethylorthosilicate in the presence of tartaric acid as template, followed by extraction with ethanol to remove the templatemolecules. The materials were characterized in detail by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption test, powder X-ray diffraction, transmission electron microscopy and X-ray energy dispersive spectroscopy. Theresults indicate that the Ti-containing silica materials have large specific surface areas (ca. 1200 m^2 g^(-1)) and pore volumes(ca. 0.900 cm^3 g^(-1)). The mesoporosity arises from disordered interconnecting channels or pores. The Ti-incorporated silicasexhibit catalytic activity for the ring-opening polymerization of ε-caprolactone, otherwise, the pure mesoporous silicamaterial shows no catalytic activity under the identical conditions.

SYNTHESIS AND CHARACTERIZATION OF STRUCTURALLY WELL-DEFINED POLYMER-INORGANIC HYBRID NANOPARTICLES VIA ATRP

Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybrid nanoparticles, 2-(4Chloromethylphenyl) ethyltriethoxysilane (CTES) was immobilized on the surface of silica nanoparticles through condensation reaction of the silanol groups on silica with triethoxysilane group of CTES. Then ATRP of St was initiated by this surface-modified silica nanoparticles bearing benzyl chloride groups, and formed PSt graft chains on the surface of silica nanoparticles. The thickness of the graft chains increased with reaction time. End group analysis confirmed the occurrence of ATRP. Thermal analysis indicated that thermal stabilization of these resulting hybrid nanoparticles also increases with polymerization conversion. The results above show that this 'grafting from' reaction could be used for the preparation of polymer-inorganic hybrid nanoparticles with controlled structure of the polymer's end groups.