Synergistic effect of aramid and basalt fibers on mechanical, thermal and dynamic properties of polylactide hybrid composites

Today's market is looking for materials that have high-strength properties and are biobased at the same time. This manuscript demonstrates the possibility of reinforcing polylactide (PLA) through the incorporation of two types of fibers to produce high-performance composites. PLA composites reinforced with aramid (AF) and basalt fibers (BF) were produced by injection molding (10 wt%, 15 wt% and 20 wt%). Manufactured materials have undergone extensive analysis including mechanical, thermal, thermodynamic and structural studies. The increase of the fiber content resulted in significantly improved mechanical properties of the materials. Composites with 20 wt% of the fibers exhibited an increase in Young's modulus of similar to 160%, and improved tensile strength by 30% compared to neat PLA. Moreover, the results indicated that each type of fiber was responsible for enhancing specific mechanical properties. AF improved Young's modulus such that for composites containing only 10 wt% of this fiber, Young's modulus increased by similar to 100%, while the same content of BF alone increased Young's modulus by 43%. In the case of tensile strength, composites with BF exhibited higher values than seen for AF with improvement of 19% compared to the case of AF where only 3% improvement was seen compared to PLA. Statistical analysis revealed that the additives had a significant impact on the change of both physical and mechanical properties. The thermomechanical tests followed a similar trend as the mechanical ones, such that a higher content of the filler caused an increase in the storage modulus. The simultaneous addition of AF and BF resulted in the same increase in the stiffness of the composites as the addition of the same weight value of expensive aramid fibers. The addition of fibers has not however changed the characteristic temperatures obtained during differential scanning calorimetry. The work presents the possibility of creating hybrid materials with tailorable mechanical and structural properties. We demonstrate that with different fibers it is possible to tune properties of polymeric composites and make them suitable for specific applications.