Development of an Electrically Conductive MDF Panel—Evaluation of Carbon Content and Resin Type

Abstract

Electronics in furniture and construction materials, in particular technologies which allow for a flexible and cable-free connection of electronics in such materials, are gaining broader interest. This study shows a further development of a concept to obtain highly conductive medium-density fibreboard panels (MDF) for furniture application. MDF were produced using two mixing processes (wet and dry) for wood and carbon fibres to investigate the effects of resin type (urea formaldehyde (UF) and polymeric methylene diphenyl diisocyanate (pMDI)) and carbon fibre content on their mechanical, physical, and electrical properties. Overall, wet mixed fibres showed better electrical but reduced mechanical properties. Modulus of elasticity (MOE) and bending strength (MOR) values of 3500 MPa and 35 MPa, respectively, and internal bond (IB) values of 0.45 to 0.65 MPa with electrical conductivities of up to 230 S/m were achieved. The technology has been successfully implemented in a demonstration object showing the application in a small piece of furniture.

Development of electrically conductive wood‐based composites using carbon nets

“…Other studies have also reported similar behavior in the electrical properties of WBP with CF. 4,32 The CF have high electrical conductivity and can significantly increase the conductivity of the composite. 31 As the mesh area of the carbon nets decreased, the number of meshes in a certain area increased, which increased the possibilities for mutual overlapping of the carbon yarns and the formation of more conductive paths throughout the panel structure to improve the conductivity.…”

“…Other researchers have also reported an improvement in the flexural properties of wood composites with CF. 4,34,43,44 The main reason for this is that when the specimens are subjected to static loading, the top (face) of the specimens is subjected to compressive stress and the bottom of the specimens is subjected to tensile stress. Since CF have a much higher compressive and tensile strength than wood and WBP, the addition of CF leads to an improvement in the compressive and tensile strength of the reinforced composite when pressure is applied perpendicular to the surface (bending force).…”

“…Moreover, the use of continuous carbon nets instead of CF reduces the carbon content in the composite. To give an illustration, the lowest electrical resistivity reported by Tschannen et al, 4 Zhang et al, 35 and Zhu and Sun, 36 in their recent work was 0.0031, 0.005, 0.1228, and 0.0525 Ω m, while the CFs content used in the composite was 10%, 30%, 65%, and 75% based on the dry mass of wood particles, Meanwhile, the lowest electrical resistivity was observed in panel type A with 1.33% carbon content with an average of 0.00053 Ω m in the present study (Table 2). It is obvious that not only did the amount of carbon used in the composite but also the electrical properties were significantly enhanced by adding carbon nets into the panel structure.…”

“…However, addressing this challenge involves finding a solution to incorporate wireless connectivity technologies into this furniture that enables flexible placement and arrangement. 3,4 To this end, various methods have been used in recent years to improve the electrical properties of wood and wood-based panels (WBP).…”

“…and the odd layers are made of wood fibers only. 4 As they report, an LED light source can be placed anywhere without the need for further cable management. However, the high CF content and the wet blending process for mixing CF with wood fibers could be a challenge for the further development of this product.…”