Fire barrier composites based on vermiculite
Ryszard Kozłowski, Krzysztof Bujnowicz, Bożena Mieleniak, Alojzy Przepiera Instytut Włókien Naturalnych, ul. Wojska Polskiego 71b, 60-630 Poznań
Annals 4 No. 11, 2004 pages 331-335
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abstract At the Institute of Natural Fibres, Department of Composites, facing composites based on exfoliated vermiculite were developed by using liquid mineral biding agents consisting of products of polycondensation of silicates and boron compounds. They have shown good fire retardant properties up to 950°C. Results of studies presented in this paper have concentrated upon modifying formulae for the manufacture of composite [2L+V] in order to reach fire proofing of the composite corresponding the class of EI 120. Advantageous results were obtained by increasing melting point of the binder [M-2L] by modifying its composition. Deformation temperature of the composite was increased also by increasing viscosity of pseudo-liquid phase formed during heating. The increase in viscosity was achieved due to the introduction of very fine particles of components of high melting points. Nine new formulae for the manufacture of composites were developed and modified composites were prepared according to them in laboratory conditions. Best results, as concerns deformation temperature of a composite (in range of 1050°C), were obtained in the case of the sample with alumina oxide. Two new formulae have been selected, according to which modified composites (in the form of solid and cellular boards) were prepared for the investigation of thermal insulating power. Figures 1-4 show clearly that thermal insulating of modified composites has been upgraded. Most advantageous formula variants were chosen for the manufacture of modified composites on a commercial scale. The products were intended for the investigation of thermal insulating power in CTO - Gdańsk, performed according to the PN-EN 1363-1 and PNEN 1634-1 standards. It results from Figures 6-8 and Table 1 that fire resistance of EI 120 was achieved for one formula variant [LG+V+AL] and thickness 60 mm. Physical and mechanical properties of fire barrier composites are presented in Table 2. It results shows that the composites are characterized by relatively low density (about 360 kg/m3) and their expansion is negligible, which means that the composites almost do not change their dimensions after soaking in water. The composites can find application to the building industry as fire barrier divisions and as a filling material to fire doors. Key words: mineral binding agent, vermiculite, fire barrier composite