Woven Structures from Natural Fibres for Reinforcing Composites

The increase of production of woven structures from natural fibres for reinforced composites can be noticed in different sectors of economy. This can be explained by limited sources of raw materials and different environmental issues, as well as European Union guidelines for car manufacture [4]. This research produced 2D textile structures of hemp yarn and polypropylene yarn and tested the impact of added glass fibre yarn on the mechanical properties of the woven structures and the composites produced from them. The woven structures were manufactured using hand looms or industrial looms (CТБ-175) using one layer technique. The mechanical testing of the reinforcements showed that the parameters of the looms had significant impact on the properties of the reinforcements. However, the desired improvement of strength by adding glass fibre to the fabric was not achieved. The one, two, three and four layer composites were produced in a hydraulic press using reinforcements woven from hemp yarn and polypropylene yarn. The mechanical testing of composites showed that the tensile strength of the composites and the tensile stress at maximum load depends on number of the reinforcement layers, but the tensile extension of the composites and the modulus of elasticity are not closely related to the number of reinforcement layers, but rather on elasticity of yarn used in weaving. Swelling of composites in water was detected.