Biodegradable Composites Applied to the Automotive Industry: The Development of a Loudspeaker Front

Abstract

The interest of the automotive industry on biodegradable and green composites is increasing dramatically due two environmental legislation that obliges automakers to reduce the disposal of waste from vehicles [1]. As an answer to this recent demand several research groups are working on the development of these composites. This work shows the development of a loudspeaker front made of two different biodegradable composites: PLA (polylactic acid) and SCA (blend of starch and cellulose acetate) reinforced with different percentages of cellulose spent fibres. The composites were previously extruded on a counter-rotating twin screw extruder and injection moulded into tensile specimens. The mechanical properties of the produced tensile specimens were assessed with an Instron Universal Testing Machine as well as the morphological aspects of the materials, studied with optical and scanning electron microscopies. After these preliminary set of tests, the best composites were chosen to produce the final parts (loudspeaker front). These parts were injection moulded on a Ferromatik Milacron K85 injection moulding machine (850 kN clamping force) and subjected to a wide set of automotive tests to evaluate their performance. The best materials for this application proved to be the PLA reinforced composites, although there is still a large window for improvement of properties, based on the engineering of the matrix/reinforcement interface and also on the improvement of the thermal properties of the PLA material.