Malaysian Journal of Analytical Sciences Vol 18 No 3 (2014): 730 - 736

 

 

 

THERMOGRAVIMETRIC ANALYSIS (TGA) PROFILE OF MODIFIED SBA-15 AT DIFFERENT AMOUNT OF ALKOXYSILANE GROUP

 

(Profil Thermografimetrik Analisis SBA-15 Berfungsi Pada Jumlah Kumpulan Alkoxysilane Yang Berlainan)

 

Norhasyimi Rahmat*, Nur Fathilah Mohd Yusof, Ezani Hafiza

 

Faculty of Chemical Engineering,

Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia

 

*Corresponding author: norhasyimi@salam.uitm.edu.my

 

 

Abstract

This study focused on mesoporous silica SBA-15 modified with alkoxysilane functional group; phenyltriethoxysilane (PTES) and vinyltriethoxysilane (VTES) using direct synthesis and post-grafting methods.  By direct synthesis method, SBA-15 templated by triblock copolymer (P123) and functionalized with alkoxysilane groups at different amount of loadings were co-condensed with tetraethyl orthosilicate (TEOS) under acidic conditions. As for post-grafting method, different loadings of alkoxysilane groups were added after co-condensation of TEOS with P123 template. Both synthesis methods used calcination process to remove surfactant template at 550°C for 5 hours. The derivatized SBA-15 was characterized by thermogravimetric analysis to evaluate the profile at different loadings of alkoxysilane groups with different synthesis method. At temperature range of 300°C-800°C, post-grafting method displayed the highest weight loss of phenyl and vinyl groups. However, there was no significant difference of weight loss for different amount of organosilane groups. In this study, TGA has shown to be significant characterization means to determine the effects of different method used in synthesizing modified SBA-15. It was shown that different loading of phenyl and vinyl groups did not affect the efficiency of surfactant removal.

 

Keywords: characterization, thermogravimetric analysis, direct synthesis, post-grafting, modified SBA-15, mesoporous silica

 

Abstrak

Kajian ini ditumpukan kepada silika mesoporus, SBA-15, yang difungsikan dengan kumpulan alkoxysilane; phenyltriethoxysilane (PTES) dan vinyltriethoxysilane (VTES) menggunakan kaedah sintesis langsung dan pos-grafting. Melalui sintesis langsung, SBA-15 yang ditemplatkan oleh triblok kopolimer (P123) dan difungsikan oleh kumpulan alkoxysilane pada jumlah berlainan telah dikondensasikan bersama tetraethyl orthosilicate (TEOS) dalam keadaan berasid. Dengan kaedah pos-grafting pula, jumlah kumpulan alkoxysilane yang berlainan ditambahkan hanya selepas kondensasi TEOS pada templat P123. Kedua-dua kaedah ini menggunakan proses pembakaran untuk menyesarkan templat surfaktan pada suhu 550°C selama 5 jam.   Derivatisasi SBA-15 telah diperincikan oleh thermografimetrik analisis untuk menilai profil pada jumlah kumpulan alkoxysilane yang berlainan bagi teknik yang berbeza. Pada rangkuman suhu 300°C-800°C, kaedah pos-grafting telah menunjukkan kehilangan berat kumpulan phenyl dan vinyl yang paling tinggi. Namun begitu, tiada perbezaan kehilangan berat yang ketara  didapati  pada jumlah kumpulan alkoxysilane yang berlainan. Dalam kajian ini juga, TGA telah membuktikan kepentingannya sebagai kaedah perincian untuk menentukan kesan teknik sintesis kefungsian SBA-15 yang berbeza. Telah dibuktikan juga bahawa jumlah kumpulan phenyl dan vinyl yang berlainan tidak memberi kesan terhadap efisiensi penyingkiran surfaktan.

 

Kata kunci: perincian, analisis thermografimetrik, sintesis langsung, pos-grafting, SBA-15 berfungsi, silika mesoporus

 

References

1.       Van Grieken, R., Iglesias, J., Morales, V. and García, R.A. (2010). Synthesis and characterization of SBA-15 materials functionalized with olefinic groups and subsequent modification through oxidation procedures. Microporous and Mesoporous Materials 131, 321-330.

2.       Kruk, M., Jaroniec, M., Ko, C.H. and Ryoo, R. (2000). Characterization of the Porous Structure of SBA-15. Chemistry of Materials 12, 1961-1968.

3.       Maria Chong, A.S., Zhao, X.S., Kustedjo, A.T. and Qiao, S.Z. (2004). Functionalization of large-pore mesoporous silicas with organosilanes by direct synthesis. Microporous and Mesoporous Materials 72, 33-42.

4.       Melero, J.A., Van Grieken, R., Morales, G. and Paniagua, M. (2007). Acidic mesoporous silica for the acetylation of glycerol: Synthesis of bioadditives to petrol fuel. Energy Fuels 21, 1782-1791.

5.       Mercier, L. and Pinnavaia, T.J. (1999). Direct synthesis of hybrid organic-inorganic nanoporous silica by a neutral amine assembly route: Structure-function control by stoichiometric incorporation of organosiloxane molecules. Chemistry of Materials 12, 188-196.

6.       Chytil, S., Haugland, L. and Blekkan, E.A. (2008). On the mechanical stability of mesoporous silica SBA-15. Microporous and Mesoporous Materials 111, 134-142.

7.       Kozlova, S.A. and Kirik, S.D. (2010). Post-synthetic activation of silanol covering in the mesostructured silicate materials MSM-41 and SBA-15. Microporous and Mesoporous Materials 133: 124-133.

8.       Pyramides, G., Robinson, J.W. and William Zito, S. (1995). The combined use of DSC and TGA for the thermal analysis of atenolol tablets. Journal of Pharmaceutical and Biomedical Analysis 13, 103-110.

9.       Lim, M.H. and Stein, A. (1999). Comparative studies of grafting and direct syntheses of inorganic-organic hybrid mesoporous materials. Chemistry of Materials 11, 3285-3295.