Tribological behavior of PLA biodegradable materials used in the automotive industry

The use of biodegradable thermoplastic materials with applicability in various industries such as automotive, consumer products, medical equipment and others has increased considerably in recent years. This increase in demand for biodegradable materials is closely linked to the growing concerns of producers and consumers alike, especially with a view to replacing, on a large scale, synthetic and non-biodegradable polymeric products. This paper presents the performance of biodegradable polymers PLA, HD PLA Green and Impact PLA Gray in terms of tribological properties, the coefficient of friction, wear and their behavior in different climatic test conditions on equipment that simulates the operation of the worm-worm wheel assembly that is part of the drive mechanism of the car wipers. The highest average value of the wear coefficient and of the wear track depth was recorded in the case of Impact PLA Gray sample followed by HD PLA Green and PLA. Regarding the results of the simulation of the operation within normal gear parameters of the worm-worm wheel (the worm wheel made from the materials proposed for this study), it was found that the mechanism ensures normal operation only for negative temperatures of use,-10°C being the temperature set as a standard in the simulations. For the other climatic conditions, i.e. higher temperatures (18-30)°C, the worm-wheel is not suitable for use.