Effect of fiber orientation on the mechanical properties of a biodegradable composite made from lyocell‐fiber reinforced polybutylene adipate terephthalate

Abstract Polymer waste in the environment is a more and more serious problem for nature. Therefore, the industry is increasingly interested in the use of materials that are biodegradable. Polybutylene adipate terephthalate (PBAT) belongs to the group of biodegradable polymers, but this polymer often does not have the desired properties for many uses. Therefore, this polymer is often mixed with other biodegradable polymers to form blends with suitable properties. An alternative is, to change the polymer's properties with the addition of fibers. The aim of the present work is to use lyocell fibers to improve the mechanical properties of PBAT. Lyocell is an eco‐friendly cellulose fiber that is biodegradable. The lyocell fibers were embedded into a PBAT matrix in the form of a woven fabric, with different orientations of the fabric warp yarns to the long axis of composites. Consequently, composites with a warp yarn orientation of 0°, ±22.5°, ±45°, ±67.5°, and 90° were prepared. The mechanical properties were characterized by quasi‐static tensile testing and also by dynamic mechanical analysis. The elastic modulus as a function of warp yarn orientation was modeled with the modified rule‐of‐mixture theory and with the theory of elasticity.