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Synthesis of microporous amorphous silica from perhydropolysilazane chemically modified with alcohol derivatives

Mohd. Sokri, Mohd. Nazri and Daiko, Yusuke and Honda, Sawao and Iwamoto, Yuji (2015) Synthesis of microporous amorphous silica from perhydropolysilazane chemically modified with alcohol derivatives. Jourl Of The Ceramic Society Of Japan, 123 (1436). pp. 292-297. ISSN 1881-803X

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Abstract

Perhydropolysilazane (PHPS) was chemical modified with alcohol derivative (ROH, R = CH3, i-C3H7, n-C5H11, n-C10H21) at the silicon (Si) of PHPS/ROH molar ratio of 4/1. The alkoxy group-functionalized PHPS was converted into amorphous silica powders by curing at 270°C to promote oxidative crosslinking, followed by pyrolysis at 600°C in air to complete the polymer/amorphous silica conversion. Thermogravimetric analysis in air of the 270°C-crosslinked PHPS showed an approximately 18%weight gain at 200 to 500°C. This weight gain was suppressed consistently with the number of carbon atoms of the alkoxy groups introduced to PHPS. Upon heating to 600°C, the PHPS modified with n-C5H11OH showed a total weight loss of 12%, and further weight loss of 31%was observed for the PHPS modified with n-C10H21OH. The nitrogen sorption analysis revealed that micropore volume of the polymer-derived amorphous silica increased consistently with the weight loss during the pyrolysis up to 600°C, and the amorphous silica derived from the PHPS modified with n-C10H21OH exhibited the highest micropore volume. Further increase in the micropore volume was achieved by increasing the Si/n-C10H21OH molar ratio from 4/1 to 2/1. The micropore volume and specific surface area of the resulting amorphous silica powders were 0.193 cm3/g and 370m2/g, respectively.

Item Type:Article
Subjects:A General Works
ID Code:58866
Deposited By: Haliza Zainal
Deposited On:04 Dec 2016 12:07
Last Modified:07 Dec 2016 15:03

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