Photocatalytic Activity and Properties of Nanotitanium Dioxide-Filled Natural Rubber in the Presence of Coupling Agents

Abstract:

Titanium dioxide (TiO₂) is normally added into the rubber compounds as a white pigment and inorganic filler for an improvement of thermal property. TiO₂ is also known to have an outstanding photocatalytic activity. This work investigates the properties of natural rubber (NR) compounds filled with 5 phr of nanoTiO₂ (n-TiO₂). Since the direct incorporation of n-TiO₂ into NR encounters incompatibility problem, therefore two types of coupling agent (i.e. bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) and isopropyl trioleyl titanate (ITT)) are used. The coupling agent loading is varied in a range of 0-20 wt% relative to the n-TiO₂. Mooney viscosities and minimum cure torque (M_L) of the compounds increase with increasing coupling agent content and the ones with ITT show higher viscosity than the mixes with TESPT. The use of TESPT leads to shorter optimum cure time and higher torque difference compared to the use of ITT. The addition of n-TiO₂ results in the improved modulus, reinforcing index and tensile strength compared to the unfilled vulcanizate. The presence of both TESPT and ITT significantly reduces a photodegradation efficiency. The difference in the properties and photocatalytic activity of n-TiO₂ filled NR having TESPT and ITT as coupling agent indicates their possible different level of dispersion and interactions at the interphases.

• Periodical: Key Engineering Materials (Volume 659)
• Pages: 474-478
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.659.474
• Online since: August 2015
• Authors: Pornsiri Toh-Ae, Banja Junhasavasdikul, Natinee Lopattananon, Kannika Sahakaro*
• Keywords: Coupling Agent, Nanotitanium Dioxide, Natural Rubber, Photocatalytic Activity

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