An experimental investigation on morphological, mechanical and thermal properties of date palm particles reinforced polyurethane composites as new ecological insulating materials in building

The rigid polyurethane (PU) with apparent density about 40 kg/m3 was prepared using commercial polyols and polyisocyanate. This reference petrochemical formulation was modified with natural and renewable components such as date palm particles (DPP). The goal of this investigation was to reduce the environmental impacts, and reduce the cost of the petroleum based polyurethane (PU) by obtaining polyurethane/date palm particles (PU-DPP) composites with the heat insulating and mechanical properties similar or better as in the case of the reference material (PU). The composites were prepared with different (DPP) loading; 5%, 10%, and 20% (by weight). The results showed that heat insulating and mechanical properties of the (PU-DPP) composites were comparable with those from reference petrochemical formulation (PU). On the other hand these mechanical and thermal performances are competitive with those of other insulating material available on the market. Hence the (PU-DPP) is a good candidate for development of efficient, low cost, and safe insulating materials

Mechanical and thermal conductivity properties of hemp fiber reinforced polyurethane composites

The aim of the present work is to introduce natural hemp fiber as reinforcement in the preparation of partially biodegradable green composites. Composite of rigid polyurethane (PU) and hemp fiber (H.F) ​​were prepared at different loading rates in (H.F) ​​(5%, 10%, 15%, 20%, 25% and 30%). Water absorption, thermal conductivity, and mechanical properties of composite were investigated as a function of fiber content. The results show that, the thermal conductivity of composites increases linearly with density. The mechanical properties of composites with 15% wt fibers loading provided a 40% increase in strength. Measured properties showed that polyurethane- hemp fibers composite present good insulating properties compared to the traditional insulation materials (glass wool, mineral wool etc.). Therefore, (PU-HF) insulation may provide a promising solution for building insulation. Keywords: Hemp fiber, Polyurethane, Resin, Green composites, Thermal conductivity, Mechanical properties, Water absorptio

Effect of surface modification on morphological, mechanical and thermal conductivity of hemp fiber: Characterization of the interface of hemp –Polyurethane composite

The study focuses on the effect of alkaline and silane treatment of hemp fibers on mechanical and thermal conductivity. Hemp fibers were treated with sodium hydroxide solutions at different concentration, and then analysed by infrared Fourier transform spectroscopy, the X-ray diffraction, mechanical tensile test; and a scanning electron microscope. The alkali fibers were subsequently treated with silane solutions and then analysed by the same techniques. Analysis results showed that the most changes caused by this treatment are, the elimination of a certain amount of lignin, wax and oils spanning the cell wall of the fibers and the transformation of some quantity of alpha to beta cellulose. These changes are at the origin of improvement on tensile strength and young's modulus of about 39% and 23% respectively when the concentration of treatment reaches 8%. This modification revealed a strong increase in the Interfacial adhesion of the fibers-polyurethane composite from 1.26 MPa for untreated fibers up to 3.18 for the alkali fibers and 5.16 for silane fibers. Moreover, the measurement of the thermal conductivity has proved that the chemical treatment increase the fibers thermal conductivity from 42.22 mW/m°K for untreated fibers to 47, 92 mW/m°K for the alkali fiber at 8%