Effects of short fibers and processing additives on HDPE composites properties reinforced with Pinus and Eucalyptus fibers

Abstract This work aimed to investigate the effect of adding short fibers of Pinus and Eucalyptus, in different granulometry (24 and 200 mesh) and concentration (0–20 m/m), combined with processing aid Struktol TPW104 (S) in obtaining of high‐density polyethylene (HDPE) composites. Overall, obtaining composites from short fibers caused relevant changes in the HDPE matrix, such as thermal stability, moisture barrier. In comparison to pure HDPE, the composites incorporated with 20% m/m of fibers, regardless of the type, decreased the melting temperature to 128°C and a wider crystallization temperature range. Another significant observation was the improvement of composites mechanical profile after adding the additive, the highest values were obtained for composites HDPEL20PS (35%—TS e 651%—EM) and HDPEL20ES (42%—TS e 681%—EM), showing good interaction and compatibility, according to scanning electron microscopy (SEM) images. The same was verified with the mechanical results of flexion and impact. Therefore, the use of short fibers and processing aid was successful providing augmented mechanical properties and thermal stability, without negatively affecting their essential properties for industrial applications.