Influence of Fe2O3-filler on the thermal properties of polystyrene

Abstract

Nowadays, filled polymers are widely used in many fields of technology. Among them, polymers containing semiconductor particles play significant roles, especially for the manufacturing of electronic devices [1]. Therefore it is important to understand the effects of these fillers on the properties of filled polymers in order to design materials with desired properties. The properties of filled polymers mostly depend on the type of materials used, of size and shape of filler particles, their concentration as well as the type of interaction between filler particles and polymer matrix. In our previous studies [2, 3] significant improvement of the thermal stability of the polystyrene (PS) matrix filled up with the hematite (Fe2O3) nanoparticles (the mean particle diameter was 5 nm) was found. This effect is consequence of high surface to bulk ratio of the Fe2O3 nanofiller. However, the synthesis route for preparation of nanocomposites is quite complex involving transfer of nanoparticles from water to organic phase. In the present study simple synthesis route for preparation of the PS-Fe2O3 filled polymer was developed based on mixing the Fe2O3-filler in sub-micrometer size range with the polymer melt. The influence of particle size of the Fe2O3-filler on the thermal properties of the PS-Fe2O3 filled polymer was discussed. Also, our goal was to examine influence of the content of inorganic phase on the thermal stability of the PS-Fe2O3 filled polymer. We synthesized the Fe2O3-filler particles by using the method of Matijevic et al. [4]. Briefly, 100 ml of 0.02 M FeCl3 was mixed with 1000 ml of 0.01 M HCl at elevated temperature (353 K). The solution was kept at elevated temperature for 24 h, and then precipitate was washed out several times with water, filtered and finally dried. In order to determine morphology and size of Fe2O3-filler particles scanning electron microscopy (SEM; Jeol JSM-3T) was used. The micrographs were taken at 0◦ tilt angle, thus making the topography contrast and shape of the particles irrelevant. Spherical Fe2O3 particles in the size range from 0.2 to 0.5 μm were observed, Fig. 1. This observation is in agreement with the results obtained by Matijevic et al. [4]. The PS-Fe2O3 filled polymers were prepared by mixing, in appropriate ratio, the Glaskar PS (PS 143 E) and the Fe2O3-filler in Haake rheometer at 473 K. The contents of inorganic phase were chosen to be 5, 10 and 17 wt%. Mixing was carried out at 32 rpm rotor speed