Porous polyurethane composites with natural fibres

In the work the methodology and results of the investigations that concern rigid polyurethane foams modified with natural fibres and oil-based polyol are presented. The goal of the investigations was to obtain the cellular, polyurethane composites with the heat insulating and mechanical properties similar or better as in the case of the reference material. The obtained polyurethane composites had apparent densities about 40 kg/m(3). The modified composites contained the considerable part of biodegradable components on the base of renewable raw materials. The influence of the rapeseed oil-based polyol, flax and hemp fibres of different length on the cell structure, closed cells content, apparent density, thermal conductivity and compression strength of the rigid polyurethane composites are analyzed. In the case of application of fibre in the amount of 5% php (per hundred polyols) the foam composites with the highest values of compressive strength and the lowest thermal conductivity were obtained. (C) 2011 Elsevier Ltd. All rights reserved.