Water absorption properties of hemp fibres reinforced PLA bio-composites

Abstract

In the development of a sustainable economy more and more emphasis is put on the development of new materials based on natural resources. Hemp fibers are one of the most environmentally friendly natural fibers with high tensile strength, retained moisture strength and other properties that make them suitable for a wide variety of industrial products. The advantage of extracting hemp fibers is that it is possible to use all parts of the plant at the same time for the production of different products - hemp seeds, their shells, hemp shives, thus maximizing the value added of this resource (the concept of sustainable development). Industrial production based on non-renewable resources, increasing demand in the consumer sphere, rapidly growing population and density puts increasing pressure on planetary resources. In this research project a biodegradable composite material is made from hemp fiber and polylactide (polymerized corn starch). Thermoset treated polylactic and hemp fiber bio-composites have high mechanical properties, which allow to reduce the amount of materials in the product. The developed bio-composite can be used both as a slab material and for molded parts of furniture, etc. In this study 3 samples of bio-composite materials with different proportion of hemp fibres in the PLA matrix were compared and their water absorption was investigated. Bio-composite hemp and polylactide (PLA) fibres were evenly blended using the carding technology. The obtained blanks were treated for thermosetting at a fixed temperature of 180 oC and a pressure of 100 kN, as well as controlled heating, compression and cooling time was applied. Bio-composite samples were tested following the water absorption standard LVS EN ISO 62:2008. Obtained material is biodegradable during the composting process, which improves the ecological assessment (Life Cycle Assessment) of the product and reduces the environmental impact. Annually renewable hemp fiber resource has the potential to create new products and develop the hemp industry in Latvia.