Comparative Study on Polyamide 11 and Polyamide 10.10 as Matrix Polymers for Biogenic Wood-Plastic Composites

Biogenic wood-plastic composites from bio-based polymers and wood fibers (bio-WPC) provide an improved sustainability and carbon footprint compared to conventional composites. Recently, such bio-WPCs from bio-based polyamides have gained major interest due to their high mechanical and thermomechanical properties. In this study, the resulting mechanical and thermo-mechanical properties of two bio-WPCs from polyamide 11 (PA11) and polyamide 10.10 (PA10.10) with a content of 30 wt% of beech wood particles (BP), processed by twin-screw compounding and subsequent injection molding, are analyzed by tensile testing and dynamic mechanical analysis. For this, two comparable grades of PA11 and PA10.10 are used. It is found that the elastic modulus, tensile strength, and the temperature-dependent storage modulus of the PA10.10/BP30 are significantly higher as compared to the PA11/BP30 material. These findings are addressed to the different number of amino groups per repeating unit in these polymers, leading to a better adhesion of the matrix and the wood fiber and consequently better mechanical and thermomechanical properties of the PA10.10/BP30. In consequence, bio-WPCs from PA10.10 should be considered as an interesting alternative with a tendency to higher mechanical and thermomechanical properties in comparison to bio-WPCs from PA11.